Hello @randv.
Unfortunately we do not currently support DTLS (which is the only good way to do encrypted UDP), the only way would be to create some sort of encrypted tunnel between the two devices (there is many options to do this on Linux available online.
Encrypted UDP is not a very common ask, and I am curious as to why TCP is not an option at all? It would be a much more reliable way to transfer the logs, as UDP can be quite sensitive to network latency.