My 2c based on my experience.
I had a i7 8700 with 4x4gb DDR4 2666mhz paired with a RTX 2070 gaming @1080x2560 resolution, I had experienced bottlenecks in most games played, Namely battlefield, Skyrim (modded), fornite and ect. I cannot remember most games I played that time it was over 3 years ago.
I can say the amount of CPU cores, IPC perf and ram config matters a lot even at budget systems especially with these modern games.
Another thing is during that era CPU's where not as performant as it should of been. e.g i paired my old i7 8700 build with a rtx 3060 ti i did see bottlenecks across the board compared to my newer 13th gen system
I would say if you are happy with how your current system, than leave it as is than do a upgrade later when ddr5 systems become cheaper.