I'm looking at OpenTelemetry because of broad tooling compatibility (both Rust tracing crates, tracing and emit, support it - for logs, tracing and metrics) and it seems like something that will stick around.

Also I'm not sure I will ever need actual performance out of an observability solution; it's a tiny app after all.

Depends entirely on the scale and frequency.

I've had an overall good experience operating it at numerous places w/o hitting bottlenecks.