A mesh has others have said. I use Google WiFi as it’s cheaper and gets the job done. But it’s a potential compromise as the more expensive mesh systems offer better bandwidth.

I tried Homeplug systems - they can work well on a well wired house, but mine was giving me about 10% of my bandwidth from the router downstairs to my home office upstairs.

For comparison Google WiFi is giving me 100% of my 250mbs connection. If you’re looking at much higher bandwidths or users, you may need a more expensive system. Alot of mesh systems have a dedicated back channel separate to the user facing channels but Google WiFi does not - that makes it cheaper but could be a bottleneck if you you’re at the very high ends of internet speeds and home usage. For most home users though I suspect Google WiFi is more than enough.