Kernel Panics..Randomly...2019 iMac 5K with Catlina driving me crazy

So I bought a new iMac in September plugged in the 3 peripherals I was using on my 2011 iMac & for some reason it kept rebooting randomly when I woke it up. I it swapped by the store for a brand new one on Saturday.

I restored from a time machine backup (first one was clean setup) and today first day I've had time to sit down & use it, it has just crashed & rebooted for the first time. Can anyone help me work out what's causing this and how to fix it?

Now I must say the store where I bought it swapped it because lots of customers were returning with similar issues. However what are the chances of them giving me the same batch assuming it was a Bach issue.

I have a Wacom Intuos Pro Small, a Datacolour Spyder 5 Pro+ a WD 2 TB Passport pleaded in. These were from my old setup along with a 27" Apple LED Cinema Display which I plugged in to these new systems for the first time last night.

I Bought a 4TB Toshiba drive on Friday to use for Time machine.

Can anyone help?