Hi! Thanks for reaching out!
You should not have to reinstall Studio One 5. You might have to reach out to Splice so they can help you remove their activation software. Once that is done, all you have to do is activate Studio One 5. If you are not automatically prompted when opening the program, go to the Studio One menu - studio one - activation and select "activate using PreSonus Sphere". Please note Studio One 5 does not require a key to activate with PreSonus Sphere, just an internet connection and your login credentials.
I hope this helps!