I have 3 TP-Link EAP-245 access points, an Omada Cloud Controller and a simple 8-ports POE switch. The coverage and stability is up to par with the Unifi AP-AC-PRO and software is pretty good, also. I can highly recommend them: much lower price point and a lifelong warranty.

Having said that, without a cable you're not going to get a decent throughput on the upper floors. Don't bother with WiFi repeaters as they'll extend the range at the cost of bandwidth.