Internet not working even though it shows i’m connected.

My PC was working perfectly fine for months, but then it randomly started having an issue where, whenever I boot it up, I can’t access any websites until I "run Network Diagnostics". After that, everything works perfectly fine, even though the entire time Windows shows that I’m connected to both Ethernet and Wi-Fi in the bottom-right corner.
I’ve tried resetting my network settings, flushing my DNS, resetting my router, and even completely reinstalling Windows. Nothing has seemed to fix the issue. I was wondering if anyone has had a similar problem, has any solutions, or has any ideas about what might be causing it.