If the control isn't for certain slots, possibly. You could always test it out to see if it has an actual impact on performance as well to see if it would allow the ribbon cable to work.
But now that I know you have PCIe 4, shielded would be minimum I would assume. Even motherboard manufactures claimed to have had a hard time with PCIe 4
Your SSD is already 3.0 anyways. I don't honestly think switching will work anyways because the signaling in hardware is still the same through the board.
OK, I redid this post. The first pic is of the previous configuration with the 1660 in place. The second pic is the new configuration with the 5700 XT mounted vertically.
No. I almost exclusively play a 6.5 year old game, Battlefield 4. The 1660 I had handled it just fine, even with the Ryzen 1600. Hell, I played it just fine when it came out and I was on a Phenom II 940 and a GTX 560 (I think). I am currently playing it on a 5760 x 1080 resolution across three 24.5 displays at 165Hz refresh rate and I have the frame rate capped at 165 (which is where it stays 99% of the time).