We use cloudflare tunnels in production for massive workloads at FiveM/Cfx.re, I can with 100% confidence say that I trust in it.

Only caveat is that if you have rapid scaling, CF might accidentally route to a non existent tunnel, and if that doesn’t resolve itself you will have to recreate it.

But this has only been an issue if you force shutdown some of the cloudflared instances. And only very intermittently, reproducing it has been difficult.