In what order should I pay down my debt?

Now I’m thinking it would be best to pay off as much of the IRS tax bill as possible, especially given GBP/USD exchange rates are more favorable than they have been in recent years.

You're right, but for the wrong reason. Exchange rate is not your problem. The problem is that the IRS has a great deal of power that they can wield to collect the debt. Maybe you're somewhat insulated from that for now by living abroad, but generally tax debt should be taken care of as soon as possible.

I don't know what the ramifications of owing money to attorneys in the UK are (do you owe the attorneys or your ex-spouse?) but that might be the next target just to keep them off of your back.

I can’t get another job

You don't say how broad your non-compete is, but I doubt it keeps you from working at all. It probably just keeps you from working in the same field. I suspect you could find other jobs that do not violate the non-compete, even if they don't pay as much.

There's not a quick fix - you have a huge hole to fill and the main shovel you have is your income. The first step is to get on a bare-bones budget so that you can put as much of your income towards the debt as possible. Every Dollar/Euro you spend is money that is not going to fixing the mess. Selling any assets (cars, property, stocks, etc.) that you don't need (regardless if they are good "investments" or not) will accelerate your progress.

not sure if relevant, I was diagnosed with both ADHD and autism as an adult in 2024.

It's not financially relevant, but might be relevant if it causes behavioral patterns that created the debt in the first place. If you can't overcome those behaviors, you may need better safeguards to stop you from overspending.

Hopefully you can find a way for those conditions to actually work for you by becoming incredibly focused on this goal.

Disclaimer: this is a partial answer, as a lot of data is missing, with no payment schedule, interest rate, assets, or left-over income numbers... a dead-on answer is just impossible.

First, and foremost, the situation is NOT desperate.

It does require acting, and you seem well aware of it, which is good.

Totals

Let's start with some accounting. You have £70,000, and you owe:

• $205,000 = $115,000 (IRS) + $69,000 (CC) + $21,000 (Parents)
• £53,000 = £28,000 (Attorneys) + £25,000 (Loan)

At current exchange rates, that's a total of £206,000 in debt, or about 3x your current money in the banks.

You clearly cannot pay everything off right now, especially as you should keep some money in the bank for emergencies. But you can definitely pay some now, and work towards paying the rest.

Schedule

In general, debt/loans are not reimbursed in one lump sum, and instead a schedule can be worked out. Your creditors have an interesting in collecting the money, after all, which is incentive for them to work with you in recovering it.

Knowing how much leeway your creditors are willing to give you can help determining the entire schedule.

Going through it all, from highest to lowest debt:

• IRS: the IRS, and tax authorities, generally don't have much pressure to collect right now, and should be willing to work out a schedule with you, to pay off the bill in a number of installments spread over years, and so at minimum cost. A 3 years plan at minimum interest would mean roughly $40,000/year. A 6 years plan roughly $20,000/year. You can apply online. Now.
• Credit Card: collection agencies will try to recover as much as possible; it's literally their business. Still, they are interested in recovering, and so may be willing to settle for either $0.5/dollar or a schedule. Contact them, negotiate, find out how much leeway you can get.
• Attorneys: I have no experience here, hopefully you can negotiate.
• Barclays: What's the schedule? What's the interest rate?
• Parents: How well do you get along? How much do they need the money? Hopefully they can just plain hold off for a few years...

For example, I note that if you can get a 6 years plan from the IRS, for this year:

• IRS: $20,000 or £15,000.
• CC (1/2): $35,000 or £26,000; either at $0.5/dollar, or pushing 1/2 to next year.
• Attorneys: £28,000.

That's a grand total of £69,000, which you already have the funds to pay right now.

This does not account for the Barclays loan, or your parents... but it also doesn't account for your income.

Mobilize your Assets

If you have other assets, you may need to sell them. Given you cashed your IRA already I am not too hopeful... but do realize that even £1,000 could be helpful here, so think hard on what you could have that could monetize.

For example, downgrading you car could both help you get some cash right now, when you need it, as well as allow you to save up on car insurance month after month. In fact, do you need the car at all right now? Can you make do with public transports?

Mobilize your Income

You mentioned you are getting paid during your non-compete. That's very helpful, obviously. The non-compete may not be binding -- especially cross-borders -- but do weigh carefully whether crossing your former employer is worth it; it may be you earn more just "respecting" the non-compete, and it's stress-free.

Your non-compete probably allows you to work outside your field. This would typically mean a lower-paying job, but it would be on top of the non-compete pay, so it adds up. Try and check around you, angling for the best paying job you can find. Even if it means doing a few months as a part-time cashier or waiter, it's all bonus pay... and you can likely get started tomorrow not far from your place.

Also, do prepare. Your non-compete, and its pay, won't last forever. Start looking for the next job now, so you have a contract starting on the day the non-compete ends. You do not want a gap in pay.

Mobilize Social Assistance

You mentioned a child with special needs. Try and see what assistance you are eligible for.

Live frugally

Don't forget to attack the problem from the other direction too.

For the next few years, you should go frugal.

Downgrade what can be downgraded. I mentioned the car, as that's typically a good chunk of a budget, but there's also the death by a thousands cut. Review any monthly/yearly payment you make, and see what you can cut from Health Insurance, Car Insurance, ... down to Spotify and Netflix.

Similarly, review your spending habits. Can you cut down on fuel? On clothings? On food? (by buying raw ingredients and cooking yourself, notably) Double-check everything. Question everything.

Anything that can be cut should be cut, anything that can be downgraded should be downgraded. Trim it down to what you're willing to tolerate.

Note: even if you can, actually, pay everything once you've worked out the schedules with your creditors, you should also be aiming to "restock" your bank account. In case the car breaks down, for example.

Work it Out

Now, the above may look drastic.

Do remember, the situation is NOT desperate.

Yet, at the same time, you're better off being pro-active about it, because otherwise your creditors will make choices for you.

So make a plan. Attack the problem from all 3 fronts (working with creditors, boosting income, reducing expenses). And grit your teeth for the few next years.