Questionable behavious when playing piece and stopping.

I assume you mean that if you select a note and then press play, the note stays selected. The playback highlight moves in time with the playback but disappears when you hit the space bar. If you then restart playback the highlight reappears at the point where it left off.

The initially selected note remains selected throughout, but that has nothing to do with the playback position, it is just a selected note. The selection does not have to be a note, it could be a rehearsal mark or a dynamic or anything else. Remaining selected is probably a good thing as you may want to edit it after stopping playback (so that is a possible reason it could be useful). And deciding what should be selected at the point where playback was is paused is going to be tricky. What if you select a rehearsal mark or dynamic as the starting point and then pause playback where there is no rehearsal mark or dynamic. Even if you select a note, which instrument should receive the selection in a multi instrument score would be another guess that MuseScore would have to make. Much simpler to leave that selection where it is.

I would disagreee, my original selection point is still quite useful for actual selection. Like if I select a note, change its pitch, then start and stop playback, and based on what i hear, I decide to change the pitch of that same note again. I expect it to be still selected. Or if I'm navigating through the score note by note using the keyboard, I don't really want playback to mess that up. Blind users especially really would be adversely affected if their selection is messed up without their specifically using a navigation command to change the selection, because the visual feedback is meaningless, they rely on things staying where they put them.

On the other hand, having some sort of optional representation of where the playback cursor is could be useful. I wouldn't want it cluttering my display most of the time while editing but there could be times when doing more intensive work with playback where it might come in handy. So a simple toggle of whether the playback cursor shows or not could be nice.