I would try the 2 pack of eero Pro 6E. You’ll probably get enough coverage with just the 2 pack, although you could get the eero Extender (or just re-use one of your existing Beacons) if you need a little bit more coverage. Just understand that you’ll likely never get gigabit speeds on any of your wireless devices—not because of eero but because your devices don’t support gigabit speeds over Wi-Fi (but you also won’t notice a difference for anything you’re normally doing).