Would thumbs this up a thousand times if I could. Never have I had such trouble getting a system to boot from a newly installed drive. I've seen countless threads about the issue of self installed M.2's not showing in BIOS' boot list (This coming from a tech savvy person who has done many of these types of hardware upgrades). Im convinced HP has some sort of BIOS function that hides the addition of drives if not factory equipped.
Running like a **bleep** cheetah now- possibly fastest startup I've ever had on a laptop. Luckily I was able to startup from the SSD again and go from there. Due to an update my computer almost immediately restarted not giving me the chance to wipe the old HD and it started up in a type of HP Recovery Suite which then lead to the Windows Recovery Starup again. After about a full 24 hours of trying everything, BIOS updates, firmware dowloads, settings adjustments this was the one solution that helped! As long as you completely wipe and clear the orginial spinning drive once you are running off the SSD it will automatically change the NVME to your main Boot.