Without access to a phone number or alternate email, your options are limited, but using the Account Recovery Page and Yahoo’s Sign-in Helper can still....
https://www.parfumo.com/forums/topic/recover-my-yahoo-account-without-phone-number-and-email

Recovering your Yahoo account without a security question or alternate email can be done through methods like phone number verification, the Sign-in Helper tool, or....
https://www.parfumo.com/forums/topic/unlock-my-yahoo-account-without-security-question-and-email

Yahoo Account Key is a feature that lets you log in without using passwords or codes. If you’ve enabled it, you can use this option....
https://www.parfumo.com/forums/topic/how-do-i-log-into-yahoo-without-a-verification-code

To recover your Facebook account without a phone number or email, use Facebook’s “Find Your Account” page or 1-888-481-0582. Enter your username, full name, or....
https://sagebusinesscloudaccounting.ideas.aha.io/ideas/S1-I-70715