I personally use Netgear Nighthawk AC1900 for myself and for my parents. Having burnt through a few other routers from various brands in the past, I find longevity of the router is basically a crapshoot. If you get a good unit, you can get 10 years, whereas a bum unit might die after 3 years and you can’t control that.
The bigger issue is that if the house is really big, and if you don’t want to manually program wifi extenders, you really need a mesh network which is more expensive, e.g. Linksys Velop or Eero.
But if I recall, head-fi meets has been at your parents‘ house before. Did they move? That home should be able to be powered by a single router.
The bigger issue is that you need 2.4GHz to cover the whole home (assuming the router is centrally located) but neighbor interference on the same band would affect the performance. My solution for my parents whose home probably is similar to yours is to have the router placed where they mostly spend their time and have their devices logged onto the 5GHz band but leave the 2.4GHz running so that they can switch to the 2.4GHz band when they’re further away and if they notice a performance drop, they can switch back to the 5GHz band. For one particularly tricky room, we did add a wi-fi extender in the end to boost performance a few years later. I did want to buy them a mesh network as an upgrade but Asian parents so they didn’t want me to spend extra money.