I have just installed pre release Version 2020 (422) as I do not rely on the software for my living.

1. The purple stuff has gone, it seems a lot quicker, and the lag seems to have gone.

2. From a quick check Lead sheets and Piano roll appear to be working.

If anyone wants me to check anything in particular before they install let me know.

I do not use a lot of the functions so some of it may be new to me. Describe what didn't work (what didn't happen) and I will check it

MacBook Pro 2020 - Big Sur 11.4
BiaB UltraPak+ 2021 Mac, (506) + pretty much everything extra.
Yamaha SLG200N
Logic Pro X - 10.6.2