Nail down following 5 topmost reasons for sucky internet.
Get the best speed by following these steps.
In somes cases as admin you might like to bypass some of the devices from login authentication and data limit. Follow the below steps to achieve that.
A lot of small routers support Openwrt but there might be some quirks with some models out there. In that case, you might like to revert back to original/stock firmware. This blog post talks about steps needed for that.
Access Point setup is needed to cover a space that can not be entirely covered by one WiFi device alone. This blog talks about setting up Access Points with a Griggi router but steps are generic enough & will work with any router.