After installing Ubuntu on a desktop next to an already installed Windows 10, I can’t enter either UEFI or Windows 10. What’s wrong?

Question

ubuntu

Does not respond to F8 and DEL during boot.
The "GNU GRAB version 2.02" window appears with the choice:
*Ubuntu
Advanced Options for Ubuntu
Windows Boot Manager
System Setup.
This window does not respond to any keystrokes and after 8 seconds Ubuntu is loaded.

Answer 1

There are also bios, with the entrance to F2. It's strange that you can't enter the bios.
The buttons do not respond because the keyboard is USB and it is disabled in the BIOS (different motherboards note this moment in different ways, look)
have you erased the UEFI partition? you need to restore it, for win it's a 100mb boot partition usually created automatically.

Answer 2

Windows Boot Manager is Windows