Can't really advise you on what to do, but here's some conaiderations:
• I still use a 4th gen i7 with 16 GB ddr3 and a gtx970, still going fine in its 10th year. Just recently upgraded to a gtx1060 I found around • 10 years old techbology isn't really any diffetent than today, only slower, but luckily architectural incompatibility is becoming less and less of a problem (except when it's forced upon for no particular reason, see win11) • gpu especially are extremely backward and forward compatible, if you only need more VRAM, you can use a modern gpu with a very old mobo and cpu and chances are you'll be as good, and even if you need to upgradr them later because you are cpu-bottleneck, you can still keep the gpu. I'm guessing in 90% of cases, pci lane speed is relatively unimportant wether it's gen3 or gen5.
Basically, upgradr when you feel you are limited in what you can do, ignore the pressure caused by the generations passing by, as time goes on, I predict we'll need less and less hardware upgrade until a nee revolutionary technology comes about that changes everything.
Imagine you are being beamup from a mission on a planet just for everyone to cheer and cry as you materialize. You are confused because they saw you 5 seconds ago but they explain that you died a gruesome death and got recovered from the last teleport buffer of you. How traumatic would that be?