What is the problem you are trying to solve?

It looks like Prometheus now has support for delta ingestion in OTLP, as in prometheus/prometheus#15165. Raising this to request corresponding support for delta temporality as well in Mimir.

Which solution do you envision (roughly)?

Expect delta temprality metrics to be ingested in Mimir as in the spec: https://opentelemetry.io/docs/specs/otel/metrics/data-model/#sums-delta-to-cumulative

Have you considered any alternatives?

The alternative is to run the deltatocumulative processor ourselves. It would be ideal if the metrics backend could support this similar to Prometheus.