linawin ko lang... you have a fibre connection, and you're having issues with both 2.4 GHz and 5 GHz WiFi bands. tama?
5GHz has higher bandwidth, but less range and ability to penetrate walls. one other thing you can check is how crowded the spectrum around you is. there are apps that show you how many wifi networks are in range. the more the NOT merrier, dahil mag-aagawan ng spectrum. using the app, try choosing a band that is free or the least crowded