Randomly Sleepy MacBook Pro Mid 2012

My Mid-2012 MacBook Pro has been having an issue for ~10 months now.

As I am typing/using my MacBook, and seemingly completely at random, my MacBook puts itself to sleep. It is very frustrating, as I have to wait for the front indicator light to start pulsing before I can wake it up again.

I have set the Computer to never sleep (display to sleep after 30 minutes of inactivity), There are not Hot Corners assigned, No Sleep Schedule. I have nothing magnetic near the computer. Sometimes it sleeps whilst I am using it on my lap, other times when it is on the desk. I have reset the NVRAM and the SMC multiple times. I have tried different chargers (when it sleeps, the charger light swaps to orange for a few minutes). It happens on both charger and battery mode.

Other people have reported similar, but none of the solutions mentioned above have worked. It is VERY frustrating, as often I am mid-task and I have to stop, wait and wake it up before I can continue.

I am running the latest available software for this model -

10.15.7 Catalina

2.6 GHz Quad-Core Intel Core i7

16 GB 1600 MHz DDR3

Intel HD Graphics 4000 1536 MB

Strangely, my serial number is unavailable, both in the About section AND in Coconut Battery...

Everything else on this machine seems to be working fine (knock wood) although the battery has seen better days... I do need to replace the battery (again!) as it only lasts ~20-30 minutes off charge these days.

Does ANYONE have any clues? This is seriously driving me nuts, and although its a great excuse to get a new M1 MacBook Pro, I don't want to simply upgrade for something with such a simple fix. I love this machine! :)