Boot off the live usb, run gparted, select nvme0n1. It shows 2 partitions, select the first one and look at the flags, it should have boot, esp. If not, enable them, tell gparted to do it. Then reboot.
Boot off the live usb, run gparted, select nvme0n1. It shows 2 partitions, select the first one and look at the flags, it should have boot, esp. If not, enable them, tell gparted to do it. Then reboot.