Beating TCP is not hard. But doing it without starving TCP sessions to death is.
The only way to co-exist gracefully with TCP is to use a compatible backoff mechanism. Anything more aggressive will basically steal all of the bandwidth from TCP and that's it.
It's worth mentioning that at least a few popular and successful games, such as Genshin Impact, use this protocol. The aforementioned is actually the only reason I knew it existed before now.
ARQ: Automatic Repeat Request[1]. This is an article about a TCP competitor boasting lower latency.
[1] https://en.wikipedia.org/wiki/Automatic_repeat_request