Do you have an upgrade budget?
With a 4790k You're looking at PCIe 3.0,
a Radeon RX 6600, 6650 XT, or 7600 are all good 8GB VRAM cards for under $250 that will last for a long time at 1080p.
VRAM concerns really only occur at higher resolutions, so for you any modern card (2022 or newer) will be a massive upgrade. The 6600 can be had for $180 these days
But even you're not planning to upgrade CPU right now, i would just buy the best GPU you can fit in your budget, and do worry about bottlenecks. One day you'll upgrade CPU/MB/RAM and the GPU will fit right in.