For the most compatibility, reliability, and performance when used with Apple devices, look for a Wi-Fi router that offers these features…
If you just have a regular-sized apartment, just get a good 802.11ac router from a reputable manufacturer, but if you need great coverage over a larger area, mesh Wi-Fi, such as Eero or their competitors, is the way to go. Personally, I wouldn’t ever get Google’s WiFi mesh solution — I simply wouldn’t trust them with so much of my data.
If you are however looking for a Time Capsule replacement, just additionally get a 2 or 4-bay QNAP NAS and configure the Time Machine backup feature on it. I have been using mine for years now and it has been flawless, better than Apple’s own product, which required me to reset my backups every few months, due to some sort of error.