"now I'm trying to figure out how to return my layout back... "
As people already tried: same Russian layout (phonetic, when A-A,O-O,...) that you used under Windows 7, can be installed under Windows 10.
Here is what such user wrote (note. I am not sure that step 3 is necessary - it was not needed under Windows 7):
"1) Download .zip of the Russian phonetic layout I used under Windows 7:
http://phonetic.WinRus.com (or same in Russian -
http://files.WinRus.com)
- Extracted all the files from that .zip. One of the files is setup.exe
- I deleted Microsoft Russian mnemonic keyboard layout
4), Started the setup. The only slowdown was the Firewall, I had to
allow the exception to run the program.
Everything works as it should now."
:-)