Failover between Starlink and cellular

Setting up automatic failover between Starlink and cellular (so if one drops, the other picks up seamlessly) needs a router that actually supports multi-WAN failover, not just having both connections available separately — Peplink and similar multi-WAN routers handle this well, but a lot of people have both connections and no actual failover logic tying them together. What router are you currently using, or starting from scratch?