Should I adjust an inflated job title on my résumé?

You can achieve the best of both worlds like this:

Official title 1 (responsibilities: A, B, C)

Official title 2 (responsibilities: D, E, F)

or

Official title 1a (internal communication) / Official title 1b (external communication) (responsibilities: A, B, C)

Official title 2a (internal communication) / Official title 2b (external communication) (responsibilities: D, E, F)

You do not lie, you do not present twisted information, you do not throw blame, you just present facts.

I would choose the first, for being easier to read.

If you choose to go with:

“Creative Solution Architect” (actually, just some JavaScript stuff)

you practically throw judgement on your previous employer for not being able to assign proper titles - which will quite surely hurt you during any current or future job hunting.