Use OLD vga Z690 gaming X ddr5

First of all I introduce myself since it is my first post in this forum, I am Juan from Argentina and my English is terrible, I used google translator to write.

My problem: I need to use a 7600GT pcie card in my new z690 gamingX ddr5 mother, both the mother with another vga, and the 7600 in an older mother work perfectly, but not together (neither a 7300gt and YES a 9800gt works correctly to give context), I tried common things like “CSM enabled” in Legacy mod, configure pcie in gen1.0 without success.

rest of the setup and some data
i5 12600k
z690 gaming X v1.0 (bios F20, with the G8 version my ram doesn’t work
ram kingston 2x8gb 6000c40)

If you could help me I would be very grateful, and if the post does not belong in this place please move and excuse me

The 7600 GT is a legacy non-EFI vga rom, as so its only supported in legacy boot as you correctly chosen, but with much years apart regarding technology against the modern Z690… a failure chance on this cases are no surprise, the only thing you can try is an updated vga rom of the 7600 GT, always as legacy boot of course.
TechpowerUp is a good source of vga roms.