So, after taking in heavy inspiration from DMARC, I built Simple Redirect Daemon (SRD).
SRD open source, and is hosted for free. Check out https://srd.sh for docs and debug tooling with record generation and inspection. For example, https://srd.sh/?r=show-hn-srd.twopow.com
I've been using this in production across many services throughout the last 6 months, and have really enjoyed the ease of use. I hope you will too!
Feedback and thoughts welcome!
P.S. to quickly see it in action: https://show-hn-srd.twopow.com + `dig TXT _srd.show-hn-srd.twopow.com`.