I set all my TTLs for a lot of things to 60sec and never much cost.
Discussion
You should probably read the following 🐶🐾🫡
https://blog.apnic.net/2019/11/12/stop-using-ridiculously-low-dns-ttls/
The comments are best part. 🤣
For geo relays I have no qualms setting low TTL for rolling other local VMs in as primary for that region.