iMac Intel 21.5" EMC 2428 - Possible GPU upgrade for Catalina (Bug Sur)

Is anyone familiar with the possible options for GPU upgrades for this devise?

I want to upgrade to Catalina and if possible after official patch or release by Dosdude1 to Big Sur and when I browse its website I can see with the current GPU the mac will be unusable due to missing to graphic acceleration.

Do you think this will be possible by updating the GPU?

I'll be grateful for any input.

Unfortunately, there's no viable GPU upgrade for the 2011 iMac (EMC 2428).

That year was the last year that particular vintage had a separate GPU "card;" after that (2012) they were integrated onto the logic board.

Besides the missing GPU support, there's going to be a number of missing drivers that you'll have to manually install because there are a number of discontined/deprecated components between the 2011 vintage and the 2014+ iMac (the official min. spec required). It might make a nice project to tinker with, but if you depend on this computer, I wouldn't invest the time as it would be the equivalent of getting a classic car to use as an Über driver - you'll spend more time "fixing" than working.