Help with Recovering My Roblox Account

I’m having trouble accessing my account. I logged out and now I can’t log back in because my account was not linked to an email. Even though I have my username and password, the system is asking for two-step verification.

I can’t use another device to log in, since I face the same issue there, and I don’t have a backup code. This account is very old and I’ve put a lot of work into it, so I would be very grateful if you could help me recover it as soon as possible.