^ TL;DR everyone expects Boba, and well, most characters to stay completely the same even after extended periods of time or traumatic events...
Even though the only reason Boba was the way he is was because of a traumatic event, that being his father dying.
A similar traumatic experience (the fall in the Sarlacc) would have huge consequences
If there's one thing to gripe about TBoBF, it's not where they went with Boba's character
TBoBF suffers from not really explaining the shift all that well (since they didn't give themselves enough time to do it on account of kickstarting Mando Season 3 way too early which was another thing) but like the actual character shift is fine