In dealing with a website, where I had to send an email using my yahoo.com through IE, I ended up with a 2nd email account on Yahoo.
I don't need 2 of the same thing, or a 2nd email account.
For bonus points, deleting Inbox stuff from the 2nd one also deleted them from my regular account, and they're really gone, not even in Trash.

The good thing about this 2nd account is I don't get the ads the original one always has in the sidebar, but the original one has a lot of emails I'm saving.
So, I guess the 2nd one needs to go, but I'm thinking deleting it may wipe out all my original stuff.

Anyone know a fix for this ?

No, but I'd change your password ASAP, to a GOOD one. Lots of scams happening right now, for whatever reason.

I have had three Yahoo accounts for over 20 years now, good to do things on different emails...

Same email address on both, as it looked like I was just accessing my email, not setting up a duplicate.

Yahoo is quirky. You initially have to set up a @yahoo.com account. From there you can create other addresses - like an email for your business if you have a domain i.e. joe@blowme.com. You cannot delete the @yahoo.com address without it killing the other ones but you can add or delete any others linked to the @yahoo.com address.

The new/duplicate deal gives me a choice to "sync emails", or to "delete from this device".
(This is on my PC - phone runs my original email & hasn't added the new one.)