From the BIOS, check to make sure that
Sata mode is set to
[AHCI Mode].
In addition, go to
Boot Option Priorities and make sure that your SSD is in that list (preferably at the top) after the initial restart.
I've had an issue like yours on MSI boards, and it always came down to the motherboard BIOS just prioritizing the wrong item in the Boot Option Priorities for some reason.
If I enter boot setup, there is no option to boot from the SSD or windows boot manager
The option should be there, as long as the drive is connected and operational. The fact that you were able to start a Windows installation proves this criteria is met.
You just cant find this option, because MSI's Bios Setup is honestly kinda terrible (IMO).
And the mode should be UEFI for a Windows 10 installation, although I think the Legacy + UEFI option works as well, because this is basically an "Auto" option.
When I was facing that problem myself (on 2 separate MSI boards), the motherboard did prioritize the right SSD disk to boot from, but in the wrong mode.
Basically, in the Boot Option Priorities, there can be a Legacy boot and a UEFI boot for each drive separately.
This is separate from the BIOS' general Boot Mode Select [LEGACY+UEFI].