Remove the bells and whistles which only add the last layer of polish to graphics, run at 1080p, and just about any decent card from the last decade will probably do the job.
I do all my gaming these days on a laptop with a weedy 960M chipset. It's absolutely fine for most things I've run recently... Metal Gear Solid V, Destiny 2, Doom 2016, Far Cry 5, and so on.
I paid £400 for a vanilla 1070 for my desktop during peak bitcoin fever. I think it's had about ten hours' use, just for VR. Worst upgrade ever. No, actually that would be the DDR2 RAM fever I got back in the Athlon days, when reading here managed to persuade me I was missing out on some miraculous overclocking sweet spot.
I wasn't.
I do fantasise about a huge, widescreen monitor and a bank of the latest cards to power it, but I don't do sim racing any more and rarely fire up a flight sim, so I don't run anything which would make the most of it even if I had the disposable cash. Which I definitely don't these days.