PCIEx16 drops to x 8 when M2 SSD is installed???

If you buy an SSD external drive to connect to your PC, there will most likely be a SATA SSD inside slot If your motherboard does

kjolley · Insert the drive · Go into bios and turn off fast boot and secure boot · Restarted the PC · Someone said spam f8 to bring up boot

m2 pcie slot I am looking to build a new PC with a 4090 GPU and an M2 ssd

m2 pcie 40 in 30 slot PC Components · Form Factor: 2280 · Interface: PCI-Express x4, NVMe · Total Capacity: 2000GB* · Sequential Read Speed : up to 2400 MBs** · Sequential