In @opentelemetry/api v1.9.0 support was added to the metrics API for creating a synchronous gauge: https://github.com/open-telemetry/opentelemetry-js/blob/main/api/CHANGELOG.md#190
See: open-telemetry/opentelemetry-js#4296

We should see what we need to do to add support for that to our OTel bridge metrics support. At the least adding to test/opentelemetry-metrics/...