Here is how we have improved our WiFi at multiple locations:
1. Replace consumer-grade WiFi gear with enterprise-grade gear
2. Add additional WiFi radios to increase coverage zones
Why replace consumer-grade Netgear/Belkin/Linksys/TP-Link WiFi gear with enterprise-grade gear? Because enterprise-grade WiFi gear will let you deploy multiple access points that will allow for seamless roaming from one access point to another. Consumer-grade access points don’t do that. In addition to roaming, the coverage provided by enterprise-grade access points is generally much better and will cover a larger area.
The gear we recommend is the Ubiquity UniFi line. The difference between the Pro and Lite versions of their access points are:
Lite version has a 2×2 MIMO radio and is indoor-only
Pro version has a 3×3 MIMO radio, is indoor/outdoor and has a 2nd ethernet port for connecting wired devices
The best news is that the cost of these Ubiquiti radios is the same or less than the consumer-grade radios they are replacing.
https://www.amazon.com/Ubiquiti-Networks-802-11ac-Dual-Radio-UAP-AC-PRO-US/dp/B015PRO512/
https://www.amazon.com/Ubiquiti-Networks-Dual-Band-passive-UAP-AC-LITE/dp/B016K4GQVG
The CloudKey controller is optional, you can run the UniFi controller on a Windows, Mac or Linux PC – or a Raspberry Pi
https://www.amazon.com/Ubiquiti-Unifi-Security-Gateway-USG/dp/B00LV8YZLK/
the USG is a firewall/router that integrates with the UniFi Controller and allows you to manage everything from one user interface. Not required, but nice.
Replacing your current WiFi gear with an enterprise-grade set of gear will eliminate dead spots in your coverage and give you a reliable network you can trust.