How to restore Win10 on one HDD, and delete Win10 on the other, in terms of linking their partitions?

Question

Windows

The situation is as follows: 2 HDDs, each was installed according to its own Win, after it was decided to remove Win from the second disk, I deleted its Main partition via diskmgmt, the Recovery Partition and the EFI Encrypted System Partition remained there - both partitions are not deleted either via diskmgmt, not through diskpart.
On the first disk, there is a single unpartitioned (at least diskmgmt shows it as shared) space that includes: Boot Partition, Swap File, Crash Dump, Main Partition.
Partitions of the second disk are not deleted by the system because they are considered (and are in fact) associated with the first disk: when the second disk is physically disconnected, the first disk with the system does not start.
How to clean up the second disk and bring the first one back to working order?
How did they get connected at all, given that I put them independently on different disks?
An attempt was made to restore via LiveUSB, tried to restore the boot partition via "bootrec.exe / fixboot". The system denied access. Then I sequentially performed the operations "bootrec.exe / rebuildbcd", "bootrec.exe / fixmbr", "bootrec.exe / fixboot" and successfully disabled (?) LiveUSB, which now writes when activated:
Recovery
Your PC needs to be repaired
The boot configuration data for Your PC missing or contains error
file: /EFI/Microsoft/Boot/BCD
Error: 0xc000000f
That's all for now :) The
question is related to the question:

Answer 1

You need to manually make both an EFI partition and a recovery partition on the first disk. If necessary, you will need to shrink the existing partitions to make room for these two new partitions.
Look for how to create these sections in Google, there is information.
On the new EFI partition, copy everything from the EFI partition of the second drive. Don't touch the recovery partition.
If after that the computer does not boot from the first disk, try bootrec.exe / fixboot from a bootable flash drive, it should work, because. the necessary partitions on the disk will be.

Answer 2

via LiveUSB, tried to repair the boot partition via "bootrec.exe /fixboot". The system denied access. Then I sequentially performed the operations "bootrec.exe / rebuildbcd", "bootrec.exe / fixmbr", "bootrec.exe / fixboot" and successfully disabled (?) LiveUSB, which now writes when activated

Well, why did you run BCD from a flash drive? :D Come on, a well-known mistake not only for beginners, but also for pros.
If it is not clear - recreate the flash drive, and run the program only from the patient disk.
Through dickpart, you can simply do a clean, but not under the OS, of course, then everything that was exactly deleted.