To add to the point above: be careful because most apps are just gamified junk. Watch the costs too. Id suggest Coursera Mobile App iOS/Android for legit university-level content instead.

^ This. Also, get OReilly Online Learning Mobile App. Ive used it for years because reading actual documentation and textbooks on attention mechanisms is the only way to really grok the weeds.

Honestly, I went through this exact same phase last year when my commute jumped to an hour each way. I thought for sure I could master attention mechanisms on the train, but man, you gotta be careful with what is out there. Most of these learn AI apps are basically just flashcards for buzzwords. I remember dropping twenty bucks on a subscription for this one app that promised advanced neural net modules, but it was just multiple choice questions about what an epoch is. Total waste of time and money if you are already comfortable in PyTorch. You might want to consider just sticking to the mobile browser for reading ArXiv papers or technical documentation instead. I tried using those interactive code on your phone apps, but they almost always hide the actual complexity you are looking for. Be careful with anything that says it is for beginners to pros because it usually stays firmly in the beginner camp. I once spent three weeks trying to make a mobile-first coding app work for testing small RAG logic, but the environment was so stripped down that half the libraries would not even import properly. It just led to massive frustration. If you do find something that looks promising, make sure to check if it actually lets you write raw code rather than dragging blocks around. Most of these platforms are designed to keep you clicking, not actually thinking through the math or the architecture. Honestly, I ended up just downloading PDFs to my phone because the app store is a bit of a minefield for actual engineers.