A single router will not handle the requirements of today’s household. There are far too many devices contending for the “airtime” that a legacy single router provides. To add insult to injury, the wireless signal is usually not strong enough to provide a stable signal throughout a sizable house.
The fix is typically a combination of 2 things. One: Using an Ethernet connection to hardwiring devices that do not move, i.e. Smart TVs, game consoles, PCs and Laptop docking stations that are used at a desk. Two: deploying multiple access points (the radio transmitter/receiver for Wi-Fi) around the house to provide stable wireless connectivity for devices that move like phones, laptops, etc. The access points are hardwired back to the router, not a wireless mesh network. Wireless mesh networks do not work as well as advertised.
Internet speed is usually not an issue. Personally we have run our house for years on 75mbs. That speed covers our business needs, streaming services, kids gaming and more. Today’s home network has to be designed and engineered like a business system to work well.