Possibly
Your Wi-Fi is fighting your neighbors.
In apartment buildings and dense neighborhoods, the 2.4 GHz band is a war zone. Every router, microwave, baby monitor, and Bluetooth speaker fights for the same three non-overlapping channels. 5 GHz and 6 GHz are usually clearer.
Try this first · Free
Install a Wi-Fi analyzer
On Android, install WiFiman or Network Analyzer. Look at 2.4 GHz channel utilization. If it's solid red, you've found the problem. (iOS doesn't allow this kind of analysis — use a friend's Android.)
If that doesn't fix it
Force devices onto the 5 GHz SSID
Many ISP routers default to 'smart' band-steering, which often picks wrong. Disable it and split the 2.4 and 5 GHz SSIDs manually if you have to.
Fiber? No
Same Wi-Fi problem on any backbone — faster internet doesn't change neighborhood radio congestion.