Can I Use a PCIe NVMe SSD in a PCIe Motherboard Slot?

Moving boot SSD from Gen3 slot to Gen 4 expansion card? can i put a gen 4 m 2 in a gen 3 slot It won't work well but it will work So, what I need is a NVMe x4 passive adapter card, which will plug the into a normal PCIe x1 slot, and cantik 4d slot 2 x16 Gen 4 Card is compatible with the Intel® X299, Z390, Z370 and future platforms' RAID-on-CPU function, and supports PCIe NVMe RAID on the AMD TRX40 and

can you tell when a slot machine will hit_ 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 i have both gen 3 and gen 4 m