In addition to QUIC, KCP [1] is another reliable low-latency protocol that sits on top of UDP that might be interesting. And unlike RFC 9000/9001 (QUIC), encryption is optional. I haven't really seen it mentioned much outside of primarily China-focused projects, like V2Ray [2], but there is also some English information in their Git repo [2].
[1]: <https://github.com/skywind3000/kcp>
[2]: <https://www.v2fly.org/en_US/>
[3]: <https://github.com/skywind3000/kcp/blob/master/README.en.md>