How to build strong fundamentals of programming without using AI

With regard to Advice questions - which this one is - I don't think there is such a thing as an off-topic question.

How did you learn things before AI? Do that. It wasn’t that long ago.

Though I'll admit that the best days of books on the subject has passed, there are a few things I would recommend (I'll take Java programming as an example):
1. Start at the beginning. The first couple of chapters might seem boring and "lame", but without learning the basics of primitives and their differences with Objects, it'll be a lot harder later on.
2. Even if you start immediately with an IDE, make sure you understand what it does.
3. There are tons of tutorials out there, but this makes it also risky: thousands of those tutorials are set up by students themselves who, instead of "teaching" programming, should study it better. Here's an (older, but still) post to why sites like javatpoint might look professional, but are seriously lacking: https://humanoid-readable.claude-martin.ch/2015/08/27/javatpoint-sucks/
4. Be prepared to put in a lot of time.
5. Books, even when outdated, can still be more than worth the time.
Some books will never be worthless. I mean, sure, nowadays buying a book that covers J2EE wouldn't help you one bit, but when it comes to books about structures and concepts, rather than about the implementations themselves, their value will remain. For instance, Joshua Bloch's "Effective Java".
6. AI tools are not only used by learners, but also by developers "on the job". There is nothing really wrong with that, unless you simply copy-paste code you don't actually understand. The tool should help build your skill, not replace it.

w3schools.com is pretty good for just getting started and leetcode is good for practicing your problem solving.

There are plenty of good textbooks available. Asking for recommendations is off topic here.

Use Java rather than Python; the Java compiler provides more advanced control.
Study algorithms, mathematics, and applied mathematics according to your chosen field or interests (statistics, mechanics, etc.).

Also study database modeling and object modeling.
For example :
https://algs4.cs.princeton.edu/home/

You can also take online courses.
https://openclassrooms.com/en/

Otherwise, the rule, in my opinion, is: "Study, code, try, study, code, try again and again, until you no longer have any doubt about the path or paths to follow depending on the type of problem..."

Share and exchange your attempts with other students.

Explain to others what you have understood; this will strengthen your knowledge.

And above all, have fun !!!

As far as I am aware, there are still books as well as on-line, written tutorials and video tutorials. Is that not sufficient? Or are you asking for specific books and tutorials on Python (or Java)?

You are right, it depends upon yourself and source. For instance, you can use books. Also, AI is also very useful to learn fundamentals, it is really a good teacher though. In my opinion, you should solve the problem first then try to understand it by using AI as a teacher, so your skills in programming will get better step by step. AI is a helper tool not replacement. The learning procedure varies from one person to another as some may use AI to generate ready codes then learn it basically, it is also not bad method if they use it and understand deeply.