It "should" work; there was once a question about AT&T no longer working on a MOFI 4500, but mine worked just fine on a AT&T business wireless SIM until this May, when I got Starlink.
I'm assuming you still are on the grandfathered rate? One thing AT&T will do is throttle your speeds down if you stream too much.
If you get stuck, the website Wireless Joint can help.