What should I upgrade?

You can just post a looking-to-buy listing for AM4x3D. It might take a few months, but eventually, you will find it. @mysticrainman has been looking too at 5700x3d / 5800x3d - 1 unit - #30 by akg7091

I think your PC is already on the high-end side, so, there’s no immediate need to upgrade.

Unless the number of cores is the bottleneck, 5950x doesn’t seem like a significant difference.

Just wait while praying for an AM4x3D to fall into your lap, and continue playing your games.