z690 Steel Legend Dual Boot Fails

Hello. I've got the z690 Steel Legend. CPU i5-12600K, 16GB DDR4, etc. The initial setup was MOBO put in case for me by friend, then I put in my 6 or so HDD/SSD and built C: drive with software installations. After this was done and working fine, I realized this PC could be used to build the fabled "Dual Boot" PC with 1 boot for DAW. I had an extra M.2 SSD-type I placing it in Ultra M2_2 slot, and I was somehow able to get the dual boot up and working fine. It worked for several months until it the M2-SSD it was jus a bought for cheap price M2-SSD that just died recently; all had been fine. Everything else was still working fine on Main Boot; just the DAW M2 had died.
    Seeing the Hyper M2 faster slots M2_1 and M2_3, I decided to get in a WD Black's series NVME. I placed it in I think slot M2_3 although it has been also in slot M2_2 tryin ta get it to work. I was able to restore image install the DAW partition but it wouldn't boot even though it was Boot Option #1 the Boot Option # 2 the NVME with also Windows 10 Pro on it even though Boot Priority 2 overrides the Main Boot, which in disk manager it is showing the main now as an active data partition no longer bootable.
    My tech friend said he doesn't know what's going on, so now I have spent all night watching YouTube help with this related aspects topics, and I really not wanting without at least exact instructions corroborated to work I guess it doesn't work this way here or it doesn't matter here. Because I don't know what to do just a deeper quagmire than I thought? Sincerely Thanks if you can help me to get the dual boot back up and running. Peace.