Pleno is on here daily asking standard questions, so he can improve and neither of us will likely be
as good as him at any point in the near future so fire away imo. :-)
His posts tend to be a touch more interesting though. I'd very rarely label one of his posts as trivial but that is just to be expected from a player like him. I also would adopt a standard raise size instead of 4/5xing, particularly from the button.
In the spot itself flash I'd have 3xed pre. I think anything is ok as long as you raise but generally 250bb deep in tournaments I'd like to open a bit bigger.
Folding to the check/raise is fine ofc. We beat nothing and have "meh" equity vs even his weakest bluffs. What sort of range did you think he would check/raise? I think answering fundamental poker questions/situations is much more important for development at your stage than any singular strategy question you could ask, unless of course, you note you have several similar type questions/issues about the same spot.