You're always going to have a bottleneck - it's whether you 'feel' it that matters.
In this instance, it really depends what games you're playing. If they're not too CPU intensive, you could go pretty high-end.... If CPU intensive, anything too high-end would be a waste.
In terms of a fair balanced system, without more context, I'd say something up to about GTX 1070 performance class +/- (1660S, 2060, RX 6600* etc)
*Although the PCIe x8 on an RX6600 could be a performance kneecap.