I did this with PfSense at home, dual homing a 1Gig/40M Spectrum and a 1gig/1gig AT&T Fiber line.
I setup some VLANS to default to the Spectrum (download heavy, less critical such as streaming) and others to AT&T (my work and gaming, more latency and packet critical). All of them failed over to keep uptime when one went down.
The PfSense router I used cost me about $300 to build and worked fantastically, as well as being upgradeable. You can get a premade from Netgate as well (they’re the team that makes PfSense).
Downside to these is that their WAN <–> LAN throughput is disappointing (at least on the USG I tried, their Edge might be better but in the smaller units may be worth validating first). With most features turned off I barely got 800 on the fiber line, and if you wanted to use the features it dropped to about 600Mbps Mbps. The Pro model might be better but at a cost premium that, unless you’re heavy using Ubiquiti for network management rather than just APs/Switches, I don’t think is worth the cost usually.
That is intended to be used with their USG, but it may work with other items. Haven’t tried it, but it still needs a router that operates with multi-homed WAN as this is basically just the cellular modem.
