I don't think .net has anything to do with it.
Respectfully, I think it does.
MusicBee is build using .NET. I'm not sure what version it currently uses, but I can imagine that it has been updated more then once over the past 14 years.
So this would not be about another (parallel) version of MusicBee, only about what .NET version is, or maybe is going to be used.
I have no knowledge of (nor interest in) Linux to speak of, but I know that there are quite a few forum members that are successfully using Wine to run MusicBee on their Linux machines.
They are Bees too ;-)
Perhaps they can chime in if they are indeed experiencing issues that might get resolved if MusicBee would update it's .NET version?
Or, there will probably be Linux forums where this may better be asked and answered? Not sure.
edit:
It might make sense to move this thread to one of the existing Linux topics (which is what the OP is actually asking about here) to keep things a bit together and not spread all over?