NVIDIA drivers made by NVIDIA are available up to macOS High Sierra 10.13.6. So if you're on High Sierra 10.13.6 or lower, you can run any NVIDIA GPU, lol provided you download and install the NVIDIA driver from here: https://www.nvidia.com/en-us/drivers/results/162473/
The EVGA GTX 680 Firmware can be modified to run GTX 770 and 780 GPUs. It's a bit of hacking involved, however, if you ever need to do a mild upgrade, let me know and I'll try to help you. Personally, I gave up on Macs a while back because they are very expensive and just not worth the hassle. Currently, I got a Threadripper 1950X 16 core with 128GB RAM, a bunch of SSDs, and a RADEON VII 16GB GPU. Looking to upgrade soon to a 32 core Threadripper 3970X with an RTX 2080Ti GPU. I know the 3090 was just launched, but I got the 2080 months ago... it is what it is, too much to do, too little time. The time spend here on the forum is actually R&R for me.
Yes, the card I purchased was the PC version of the EVGA 680 and then I flashed their Mac-compatible firmware on it, was pretty easy. Not sure a single gen bump would be worth it at this point, particularly not in a 10 year old computer. The 680 runs WoT and everything else I play just fine.