MBA 2017 Mojave was a meh Catalina grew up really good and now is a great OS Big Sur is a *Big* meh -> rolled back I think that Big Sur is the worst release since Lion I think that the team was so focused on Apple silicon that probabily nothing will be ever optimized back for x86 cpus. I hope to be wrong but i remember back the days of PPC -> x86: Tiger GREAT, Leopard GOOD but really really better on x86, Snow Leo on Intel was a lighting and Lion was a buggy release initially, from Mavericks to El Capitan all great releases. I hope to be wrong but i think that x86 mac should continue to run on Catalina.