Limited internet speed

Something else that came to mind was how many Devices do you have running on your Wi Fi at any one time. The more Devices you have connected will slow down your Internet Connection. For Exp: Phone, X Box, Television, PC, Tablets, Alarm System, and so on. Also Check to see if you have any outside Connections or Unwanted Devices Connecting to your Wi FI.
Always make sure you keep your Wi Fi Secured and Protected as this can lead to lots of Problems from Malicious Users to Free Loaders piggy backing on your Network. Here is an Article to help you out....
https://www.technewstoday.com/how-can-you-see-what-devices-are-connected-to-your-wifi-network/