It is neigh impossible to send truly anonymous data as telemetry. As soon as you're using the internet, you're disclosing an IP address, which is PII. If you add anything to link two subsequent telemetry reports together, that thing is PII (e.g. a hash or a uuid). If the telemetry report is detailed enough that they become somewhat unique, it's PII.
That said, consent is not the only grounds on which you can process PII. Contract, legal obligation, vital interests, public task, or legitimate interests are also valid grounds. Of these, legitimate interests is the most applicable in this situation.
That said, consent is not the only grounds on which you can process PII. Contract, legal obligation, vital interests, public task, or legitimate interests are also valid grounds. Of these, legitimate interests is the most applicable in this situation.