If you are able to run Ethernet cabling to a few key, strategic points in your house, then a multiple wired AP installation like Ubiquiti UniFi is probably the best answer. You usually need one AP per floor, or one AP per 1000 square feet, but that’s a rough guide. Each AP needs an Ethernet (wired) connection. A lot of details, including links to good introductory videos, in another thread:
If you don’t have and cannot run data cabling to a few key locations, then a mesh network is probably the best answer. Eero is very good. I don’t have hands-on experience with it, but from what I’ve read, you are better off spending a bit more for their higher-end units.
Both UniFi and Eero can run in either mesh or multi-AP mode. Eero is the better mesh solution today. Ubiquiti is (probably) the better hardwired multi-AP solution today.
I like to say Eero is the Apple of consumer (easier) wireless networking, while Ubiquiti is the Apple of prosumer (easy enough, powerful) networking. Another metaphor might be iPad vs. MacBook.
Don’t bother with wireless range extenders. They’re basically the most primitive version of a mesh network you can imagine. (Like that first fish that walked on land, range extenders are a relic of an earlier time.) Skip the extender, go straight to modern mesh networking.