Definitely don’t use the extender. I have seen people have good results with an Orbi mesh, but everyone always says a Unifi mesh has perfect results even though it’s a bit pricey. I tried Orbi but I ended up with more dead spots than with my single Asus wireless router. I believe Asus also has a mesh option but again I haven’t used it. I would honestly pick one that meets you budget and try it out, at worst you have to return it for a full refund.