Can i save and quit minecraft between a AA run for 3 or 4 hours ???

you can but you need to record you quitting the world and joining it back. you also can't do anything else on that instance of minecraft during that time

As long as you show it in the recording and it's not used for anything considered a glitch it's fine (e.g. don't do it while in lava or falling from a height cause then the 3 seconds of immunity comes into play, unless it's for the glitched category). And don't create or open another world unless you're doing it on another instance, as the files can interact with each other. All Advancements is officially segmentable due to its length and the fact that saving and quitting every few hours here isn't very exploitable, unlike All Versions, so this is completely fine. Just try not to do it too many times in one run.