How to know if my router has been hacked?

I have a (maybe dumb) question for you. I was wondering if there is a way to know if my router has been hacked.

I secured it the best that I can and also made it so only the mac addresses of the devices that I know can access my WiFi.

I turned off uspn, WPS, and remote access to the router settings even though I noticed that the page won’t load anymore on the device I used to set it up but it loads on my phone.

While days ago it would not load on my phone but it would on other devices but I keep seeing accesses to my social medias by devices that seem to be mine but I nor everyone else in my family used lately.

I’m afraid someone hacked my router and is using my devices remotely. How can I be sure? Would calling my ISP help? My router is from my ISP.