Best practice for Internet/WAN failover?

Hi All!

I have been using various Ubiquiti Edgerouters for dual WAN connections with failover or load-balancing, but would like to implement this on an AlmaLinux 9 box.
I haven’t been able to find any good How-To / Best Practice / Recommended implementation docs for doing this.
Basically, one NIC will be for the internal LAN. 2nd NIC will be connected to primary ISP, and 3rd NIC will be for backup ISP. If primary ISP goes down, default route / all internet connections, etc. go to backup ISP on 3rd NIC.
Any good “best way to do this” documents/guides for WAN failover?