Trouble Deleting Old Instagram Account

For context for the rest of the post, Hotmail is my old account, Gmail is my new account.

I created an Instagram account years and years ago on my Hotmail account. It was also linked to my Facebook account and my Meta Headset account.

I created a new account using my Gmail account.

I unlinked my Facebook and Meta Headset account from the Hotmail account and linked them up to my Gmail account.

HOWEVER...if I try to log in to my Hotmail account (on my phone as the profile is still there) for some reason it's logging me into my new Gmail account instead of the old one.

I want to delete my old one so as not to confuse friends I'm following now on my new one, thinking it could be a fake account.

Has anyone else had this happen, and is there a solution? Not sure if trying logging in on a computer might be any different?

Any help greatly appreciated!