Main Windows deleted from 2 Windows installations, now PC no longer starts?

So I bought a new SSD and now reinstalled Windows on it to be able to use it as the main SSD. However, for security reasons I left my previous Windows installation on my old SSD. This always brought me to a Windows Boot Manager where I could choose whether the old Windows should start on the old SSD or the new Windows on the new SSD. So far okay.

But now I have formatted the old Windows from the old SSD and wanted to use the old SSD for my Xbox. The problem now, however, is that my new Windows no longer wants to start without the old SSD. So as soon as I remove this SSD from my PC, I always end up directly in the BIOS, although the Windows I want to use is on the other new SSD. When I reinstall the old SSD (although it is formatted) in my PC, my Windows starts again, but in a "Windows To-Go mode". Even if I pull out the empty old SSD during operation, my Windows hangs even though Windows is installed on the new SSD.

It seems that Windows still has some important files on the old SSD that are needed for booting, as the old Windows installation was there. I would now reluctantly reinstall my Windows on the new SSD because I've been using it for a few days and then I would have to reinstall everything.

Below are pictures of the partitions. It is also strange that there are 2 partitions on the old SSD that I can't format.

The boot sequence is set correctly in the BIOS.

On the new SSD the partition that is on the old SSD is missing, namely the one with 577 MB, I don't think you can just drag it to the new one.

Did you still have the old SSD in when you reinstalled?

Yes I had. As a result, I then had 2 Windows installations in parallel

You are missing a bootloader. Google times how you can install on the new disk