Ctrl+B, Ctrl+F, Ctrl+I and other hotkeys don’t work in case of different keyboard language layout. It is first time when I met this behaviour.
Usually these combinations works in any software in any keboard layout, so Ctrl+B (in rus layout will be Ctrl+И).
I think that automatic behaviour of Obsidian should understand that if Ctrl key is locked, than the next letter would be a command, so I expect result of the command without changing keyboard layout.
Current workaround (optional)
Now I need to change language to En, press command Ctrl+XX and than change it back to Ru.