Cheapest 4k capable graphics card?

I have recently gained a 4k monitor but had to give away my 1080p one. My Nvidia 2060 is therefore struggling with anything more complicated than League of legends.

I would like to be able to play multiplayer games like fellowship, path of exile 2, maybe jump space, at a stable 30FPS or better.

Money is an issue, what should I be looking for?

Edit for clarification:

• the 4k monitor was a gift from a close family member. I can't sell it but I can run it at a lower resolution for a while.

• having received such a gift, I gave my 1080p monitor to a friend in need. The friend needs it for studies, I can't take it back.

• I didn't state a budget because otherwise it just becomes a "what's the best GPU you can buy for £X" thread. The point was to assess what I might need to spend, to get 30+ fps on a 4k monitor, playing on low to mid settings. Sorry if this makes you unhappy.