Logic glitching at 48khz sample rate since updating to Big Sur

Recently updated OS to big sur.

I just started a new project in logic set to 48khz sample rate.

I recorded a few tracks in which seemed ok but then, when I had a few playing together and with plug ins added, the whole sound started to glitch badly until it finally completely cut all audio.

when I close down and restart logic it works for a few seconds until it does the same again.

trying to record in new tracks is impossible as it lags terribly and then again cuts all sound after glitching.

it’s like it can’t handle more than a few tracks at that sample rate.

never had this issue before in Catalina so wondering if it’s the OS or if there’s something else I need to look at?

ive tried running it from an SSD to see if that would help but exact same problem. I’ve opened up much bigger projects which were at 44.1khz and they run absolutely fine.