The usual answer I've found to this question is Microtik, they strike a similar balance between enterprise feature-set and more consumer level price point as Ubiquiti sort of aims for with the Unifi line.

The quality/feature set is there and the software is well designed, even if not quite as networking beginner-friendly as Unifi has become. Mikrotik's RouterOS can do much the same tasks as Unifi's management console, and can configure for auto-adoption of APs/other hardware in the Mikrotik range just like Unifi does for their own hardware.

Most competitors (I see Aruba suggested) are priced much more into the enterprise/business buyer realm. Unifi has generally been keenly priced in this market, their latest Wifi 6 APs are just 99 dollars each (when in stock of course...). Microtik's pricing is generally comparable or cheaper than Unifi in my experience.

https://mikrotik.com/