I’m not aware of an auto search function.
Beko make a lot of unbranded TV’s:
006, 144, 086, 145, 111, 064, 072,
172, 361, 405
so I’d try these first.
There must be some identification on the TV, serial number, model number, country of origin etc. something that would help identify the make.
Alternatively some of the learning all in one remotes will connect online to a database and I’m sure it will suggest models if you learn a command from your existing remote.
Alternatively, again, there doesn’t seem many codes above 500. You’d expect to hit the right code after 250 attempts, do 50 a night whilst watching wallpaper TV starting at 000 and you should have it sorted in a week