Why is my WiFi constantly disconnecting and how can I fix it?

I've been having trouble with my PC disconnecting from the WiFi consistently over the past few days. I've tried running the troubleshooter and a bunch of guides, but no luck. I'm getting a few specific error messages like "The default gateway is not available," and "your computer appears to be correctly configured but the device or resource (DNS server) is not responding."

So far, I've attempted several fixes including turning off power management for the network adapter, updating the adapter drivers, using command lines like flushdns and netsh, reinstalling the adapter, and unplugging the router. The only thing I've successfully addressed was an issue with "excessive roaming" by changing roaming sensitivity after the driver update.

It seems like it's not just my PC that has issues; my TV might be having problems too. I'm really not sure what to try next.