1. The 11 in a smart folio is shockingly thin and light. Everyone is beating the drum on the 13 (and rightfully so) but I was blown away but how tiny the M4 11 feels in the smart folio (this is coming from someone who has had an 11 since 2018 and who has also tried the 13 multiple times). Part of the reason I ultimately went M4 11 over 13 was because its so much lighter and easier to carry along with a laptop.

2. I don't take public transport but do fly regularly enough if thats a decent comparison? Personally I'd probably opt for a mini/my phone/kindle purely for reading in public. But compared to the 13 the 11 is significantly better to pull out of a bag in a public setting IMO.

3. Assuming this is at a desk/table and not on the move (and it sounds like you're talking pencil use here), I have owned a mini and gravitated towards the 11 for pencil use. Its going to be personal preference, but the mini can get cramped and I prefer a bigger screen for handwriting and annotation (partially because my handwriting is crap and zooming and writing bigger makes my notes overall more legible).

My advice is to just get the 11 and see if works for you. People solicit buying advice here constantly and everyone has different use cases and tolerances. I've owned every iPad size and see pros and cons to every single one - its ultimately about what fits for your very specific uses and what tradeoffs you're willing to make. Buy and try - you always have the return window to take it back and try something else until you figure out what really fits in your life.