Actually no, it doesn't matter who controls the exit nodes as long as your only concern is keeping your IP private. (Exit nodes can indeed do bad things to unencrypted traffic, but that's irrelevant for this use case.)

Latency also doesn't matter here; this telemetry could take 5 minutes to reach its destination and it wouldn't matter, so long as the data is eventually received.

Hmm, I've never thought of that. I like your idea.