Email address was hacked. What are the hackers going to do?

I noticed when I was attempting to sign into my outlook email that the website looked like it was malfunctioning - code all over the page and whatnot. The page finally loaded and I was able to log in.

It wasn’t until an hour later that I got an email to my connected email address that there was unusual sign-in activity on my outlook (in “Malaysia” - though I’m sure it was a VPN scrambler). It was a successful sign-in.

I immediately reported the activity as suspicious, changed my outlook password and did all the things - added 2FA, alias, etc. But it looked like the hacker didn’t do anything in the account.

What was / is their plan of action? Did they download all of my emails? (Thousands and thousands of junk emails but some had information in them) Steal my info? Why would it appear as though they didn’t do anything?

Stressing about the possibilities and would just like to know what I’m up against in my future.