If you want more info on why people are suggesting you dont need to worry too much about the pci express 3.0 being a bottleneck, Gamers Nexus has done great videos on the subject over the years. The video where they compared PCI Express 3.0 vs PCI Express 4.0 performance on a 4090 is worth watching.
In General PCI Express 3.0 does not bottleneck a 4090 except in certain titles, or at low resolution.
The 4070, 4070ti, 7800, or 7900 GRE are all 16x pci express cards. They are all much less powerful than the 4090 so generally will be less demanding (unless you run out of VRAM).
If you buy a card with enough VRAM for what you are doing, and you get a 16x pci express card, you are not likely to bottleneck from the pci express bus.
Its not a direct apples to apples comparison, but, consider that the 4090 is a powerhouse, and really only gets at worst 15% hobbled at 1080p in some games. And less than 2% performance difference pxi-express 3.0 vs 4.0 in 1440p, 4k, and most games even at 1080p.