Hi there.
No Kepler Nvidia cards are supported after Big Sur. However
a patch has been created which allows Kepler GPUs to run under Monterey. Say, a GT710 or GT730 (I haven't tested).
It's a big shame. AMD cards are still too expensive unless you get lucky. An RX560 is, perhaps, the cheapest reliable option and a Dell OEM AMD RX560 GPU can often be found on Ebay for around €100. I imported one from the US.
Some people will tell you that an RX550 can be made to run, but this is very tricky - and there are two versions, one with a Lexa core which is
not compatible. The Baffin core version
is. The trouble is, it is difficult to know which is in which GPU unless you can test.
@trs96 will probably have some better ideas.