There’s something wrong if it takes 20 minutes to save. That is definitely not normal. I suspect the overuse-of-lasso-problem, which makes the file explode (in size) if you keep using the lasso and ignoring the warning.
We do in fact have autosave done by now. Also we have finalised an great solution for the oversuse-of-lasso-problem. This is included in our next release (Alpha 8).
To clean up your file now, I recommend sticking to what the warning suggests. More about it here: https://animationpaper.com/forums/topic/software-consistently-crashing/