GPU not working on pcie 5.0 slot but on 4.0 slot instead.

I recently upgraded my motherboard and cpu to a Tuf B650 Plus wifi paired with a 7600x3d. When i completed the build and used my rx 6600 to boot it up it wouldn't turn on. I then switched out the rx6600 with my old rx 6500xt into the pcie 5 slot and it worked and gave me no trouble at all. I later then tried to insert my rx6600 into the pcie 4.0 slot and it worked and booted up. What sort of issue am I running into with my rx6600 not being able to be booted up when I put it into the pcie 5 slot?