The older ones all have an Ethernet out. When you setup, one become the router and the rest are wifi points with a Ethernet out. The devices are all the same but once you configure the main one it is the only router. I just looked and this looks pretty simple to do in the google home app.
you can also get another nest router and configure it to be a mesh node. This would be the best in terms of speed but is likely more tricky to do the setup. You don’t want two routers even tho it may seem to work for a bit.
google is your friend here.