If you're not satisfied with the low-TTL/round-robin strategy, you would need to build out some private infrastructure to perform routing failover.
A tunnel with private routers between two cloud providers would allow you to advertise private host routes (/32) inside your network while NAT-ing appropriately to the outside. This achieves manual failover (or fast migration), but it can be expanded for dynamic failover, as well.
Let me know if you'd like me to elaborate the above solution. Otherwise, good luck with whatever solution you choose.
A tunnel with private routers between two cloud providers would allow you to advertise private host routes (/32) inside your network while NAT-ing appropriately to the outside. This achieves manual failover (or fast migration), but it can be expanded for dynamic failover, as well.
Let me know if you'd like me to elaborate the above solution. Otherwise, good luck with whatever solution you choose.