Processor may be a limiting factor going forward, as well as PCIE Gen 3 slot on motherboard, but you should still be able to get the majority of performance put of most GPUs. Look for Radeon 6600 or 6600 XT in your local market, or if you can find an RTX 2070 for a good price.
Going newer, a 4060 would also be a good choice, and DLS3 would be a good feature in your build, but that's pushing a little past your budget unless you find a good sale or used one.
Yeah, it's at most a 10% decrease, but didn't want to mislead on it.