Question

if I try to activate studio one with sphere it is still registered to the old (bought) version and I can't activate extensions etc

Answer 1

I'm also having the same issues. Bought Studio One 5 Artist prior to buying my Sphere subscription and now my software seems to be stuck on the Artist version, I have some functionality of the Professional(some plugin access but not all) but when I open the software it still has Artist at the top.