The 1.0 specification for counters reads:

The MetricPoint's Total Value Sample MetricName MUST have the suffix "_total".

I propose this should be changed to SHOULD have the suffix "_total" for 2.0.

It is a best practice in Prometheus to suffix counters with _total, but other libraries, such as OpenTelemetry, include counters without a _total suffix. It is much nicer to be able to query for rate({"my.counter"}[5m]) than rate({"my.counter_total"}[5m]) for a metric defined as "my.counter".