Moved into new apartment complex with internet included, getting frequent portscan alerts on multiple devices

Basically what the title says. My new place includes internet in rent - I get my own router/access point with its own password, but I assume all the units in my building share the same modem.

Ever since I connected to the network, both my personal laptop and my work laptop - different anti-virus suites between the two - have notified me of frequent portscans (with the latter actually blocking my network access as a result). I've never had this happen before on either.

I also don't have admin access to the router so I can't see as much detail about the network as I would like. However, the issue *appears* to go away when I connect direct via ethernet.

I am not super familiar with port scans (or networking) in general, so apologies if these are silly questions, but is this something I should be concerned about/is there anything I can really do to fix this?

Other questions:

Could it be just a router glitch/issue?

Could this be a result of a bad-acting device connected to my network that shouldn't be?

Could I fix the issue by just buying a new router to replace the one that came with the apartment?

Thanks so much!