Would it be possible to add a feature where task can be marked as 'unbreakable' i.e. if there is, say, 1.5h planned for it, Sunsama will only ever schedule it in one block of that length? Then, going further, a minimum size for the chunk could also be settable - for example, 2 chunks of 45min may still be doable.

What I find is that sometimes Sunsama tries to squeeze task in too many / too small chunks and it just will never work in practise, with context switching / overruns / etc. and then I have to 'work the tool' to wrangle it to do what I want, so it adds friction.