On the step 1 of recovery, have you clicked "+ Add Pubkey" to add another text box where you can put the second xpub?
How about the recovery tool from the actual/updated domain? (recovery.btc.com)

Anyways, here's the archived version of their official announcement when they terminated the wallet service,
link: https://web.archive.org/web/20220331180654mp_/https://wallet.btc.com/#/announcement
It has a link to their recovery support email that you can try if they are still active.

Maybe unrelated but, there was also a discussion here at that time: https://bitcointalk.org/index.php?topic=5386357.0