Need help recovering my Instagram account — lost phone number, no email, no password

I’m trying to recover an old Instagram account.

Here’s my situation:

- I know the account's username.

- I don't remember the password.

- There was no recovery email connected to the account.

- The phone number that was connected to the account is no longer mine and has been reassigned to someone else.

- I have another Instagram account that was also using the same phone number, and I still have access to that account and know its password.

- I also have the old phone that was previously logged into the account, but the phone is currently completely dead.

Is there any legitimate way to recover the account in this situation?

Could the fact that I still have access to another Instagram account that used the same phone number help with recovery?

And could the old phone being previously logged into the account help, if I manage to get it working again?

I’m looking for legitimate recovery methods, not account hacking or bypassing security.

Thanks.