(This is my own channel), but I recently made a video on Objective C calling conventions specifically for Reverse Engineers that you might enjoy, with more iOS videos incoming:

https://youtu.be/eI-Btfjp-fg

As for modern RE resources, I can recommend Jonathan Levin's series of books on MacOS and iOS internals as a good reference. It's probably the newest information you are going to be able to get on iOS/mac internals outside of apple.

https://newosxbook.com/

Nothing comes to mind that’s similar to that first link. I’m really just replying to emphasize to others how great it is. I learned a ton from it.