My house is too small to require a mesh wifi system. The router works pretty well when there are four rooms and they are two up, two down. There are a couple of areas of weak signal, especially when using 5G because there are brick walls in the way. A quick swap to 2.4G and it’s sorted though. The 5G signal has a higher bandwidth but the higher frequency doesn’t penentrate solid substances as well as the 2.4G signal.
I have installed a mesh at another house. It was a mostly harmless process. The TP-Link Deco system connects to the internet modem with an ethernet cable and then it all works! I did have to log in to the modem/router and tell it to turn off the wifi that it produces. Then everything is connected via the Deco unit. There are two mesh wifi transmitters and also a LAN going to a simple switch that connects the entertainment stuff up to the internet.
There is a gaming console connected to part of the extension of the mesh and even thgough there is a double wifi lan connection to the internet there haven’t been any complaints about latency. I am impressed.