I found a working 2011 21” iMac in the trash at my school. Need help with egpu setup

If this is the wrong community, please redirect me to a more fitting one, thank you.

The Mac has a poor 4gb of ram which I’ll be upgrading to 32gb very soon. The only issue I can’t seem to figure out is that the gpu is shit. (AMD Radeon HD 6770M 512 MB)

Does anybody have experience with this? My iMac is currently running on 10.12.6. Please let me know if there are compatible any egpu with this computer or if it’s a lost cause.

I mainly want to do a lot of 3D rendering, video, and audio editing and would love this fucking piece of junk if it ran beautifully.