1) I am aware if the crash when using drag and drop on Catalina, it seems to be an incompatibility with the current development environment. Best advice I can give is to update to Big Sur.
2) Not sure, but I think this is another Catalina issue. Will check it on Sonoma,
3) That’s normal. I wanted to prevent overloading the queue with too many songs, 60 songs will play for at least 4 hours that is enough for a gig especially as you will most likely select a new song manually sometimes within these 4 hours.
4) which command exactly did you assign?