I understand the concern. It can be a great convenience to not run the servers yourself, as people have been doing for decades with respect to websites, apps and APIs. That's essentially the same model, with the host terminating HTTPS for you.
> ...lossy UDP
All networks are lossy, and all transports. The difference between UDP and TCP based transports is who decides how to handle it. With UDP the application developer decides; with TCP (and QUIC) the protocol decides. More and more projects are taking-on the reliability decision, for a lot of reasons that trace back to this difference.
> ..some random guys on the Internet
Essentially; and that's how everything starts. We've been in production since early last year and have maintained >99.99% availability. We're a certified partner with AWS, and have "qualified software" (it passed their security review), and our security posture report is available from AWS Marketplace. We aren't SOC-2 audited yet because we want to do it right rather than pay for a rubber-stamp report, and that takes time and a lot of money.