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There are two major routes (other than using one combined WiFi/router):

1. Setting up enough wired Access Points to cover the house.
2. Using mesh AP's to do the same, without running Ethernet to each.

First option can be made arbitrary easy or complicated (PoE, Ubiquity, home-made OpenWRT etc.) but is the most robust.
Second option is slightly slower but plug and play. If you are only accessing Internet and do not have fibre, it is plenty enough. (I helped neighbour to set up Asus Lyra mesh system. It works fine.)

Wired AP's are the best solution, but overkill in most cases. I use four former 801.11ac Internet routers as Access Points (re-flashed with custom Linux OS, customized as dumb AP's, with quick roaming enabled) and one central router. I have 500Mbit WiFi link speed everywhere for 200 bucks but have spent lot's of time fine-tuning. Ubiquity kit does the same, but with hefty price markup (obviously).

P.S. Also, use Ethernet cable for everything that is not moving and has Ethernet jack. WiFi is meant for mobile stuff.