Cerlancism

However I have an other HDD connected, but no boot data should be there as it is a data drive. I will try to disconnect it also now.

Already disconnected old drive. However, the old slot is a sata only m.2 slot. Basically my new drive currently is at the other slot supporting pcie. Which means I also can't move it to the slot the previous boot drive is using

Already tried BCDEdit and full reinstall.

I recently transferred my OS from m.2 SATA SSD to m.2 NVME SSD using EASUS todo backup clone function. Everything worked fine but if it gets restarted it will stuck at boot up showing "Checking media presence , no media present" indicating missing boot device. However, turning it off and on using the power button it will boot normally again. Now I tried a full reinstall Windows this weird behaviour still persist. Is there possibly a BIOS issue of my machine when using a NVME SSD? It is a custom build Clover Laptop.