@TheZNerd Thanks fot the informantion, there are 3 years support in .Net Core lts version like .Net Core 3.1 and .Net Core 3.0 still can using right now just not support from MS.
So most user using UWP app or Desktop app with Up Framework(supported Windows Apis and EAPI) to control GPIO, just few user using .Net Core 3+, so maybe you can considering to using .Net Core 3.1 first and transfer to .Net 5+ when Up Framework is .Net 5+ ready.
We'll plan to support .Net 5+ into Up Framework ASAP, thanks.