installing Gen4 NVME on a Gen3 Motherboard

First of all, I know that a PCIe 4 SSD NVMe will be running at gen 3 speeds and bottlenecked by the PCIe 3 slot But I'm wondering if there are

2 slot switches the GPU slot slot to 8x gen 5 But there aren't gen 5 lanes only, and 20 gen 4 lanes For a motherboard to support

m2 slot screw You may experience drives dropping, parity errors and or format failures with all MegaRAID and 3ware RAID controllers if you have a PCIe GEN 3 motherboard

m2 pcie slot These generations of industrial computing solutions specifically dedicate PCIe Gen lanes directly for an onboard NVMe storage solution