restore from time machine to solve speed issues?

I bought a brand new studio M1 when they came out to replace my mid 2015 iMac 27" and used migration assistant to move everything over. the hope was that my silicone native CAD software would run faster and smoother on this vastly superior machine. not so. quite disappointed, there is hardly any difference at all. 3D rendering is faster for sure, but i'm still plagued by one main issue, among others, a spinning beach ball, when i save the projects. it's best practice to constantly save the work as you go and every time i do, i get the spinning beach ball for about 2 sec. my old machine did the same thing. this is not the behaviour others running the same software on the same machines are experiencing. everyone else on the CAD forums have said they've seen great performance improvements with the studio. it's been suggested that i've brought the issues over with the migration. i thought i wanted to do a clean install and manually bring my stuff over, but others here say that's asking for trouble. is restoring from time machine not the exact same thing? won't i just be bringing the problems right back over again? i don't mind reinstalling all my third party software manually, but i really don't want to risk losing passwords, photos, music, etc. what's the best way to basically restore my machine to new and get only my personal info and prefs moved over, while hopefully leaving behind the gremlins causing my performance issues?

ps. a friend of mine has the same machine with the same build, so i installed the CAD software on it and opened a project of mine from a thumb drive and his machine performed better and didn't have the spinning beach ball issue. so there.