When using M.2 SSDs, make sure that you do not use the last two SATA ports as M.2 uses the SATA channels. i had this problem where the M.2 SSD took forever to boot Windows. i had used SATA ports5-8 and the M.2 uses the SATA channels for SATA7-8. When i reconnected my SATA devices to SATA ports 1-4, all was well...
It still applies... If you use any SATA ports, you must use them in order. M.2 or NVME M.2 SSDs, it still applies as M.2 ports are not really dedicated.