1. No telemetry. Hope that people report things accurately
2. Opt-in telemetry. Hope that enough people opt in to give something statistically accurate
These are the only options if you do not want to treat your users as a commodity. Only despicable companies and individuals use opt-out telemetry.
Issues with (1) and (2) are that only those who are positively engaged + more technical are likely to opt in or report.
Is that a real problem? With my software, I actually want to get the feedback from the people that are engaged with it the most.