It's 8mb dll when compiled fully as dll(s). Check the https://github.com/open-telemetry/opentelemetry-cpp as they've recently added dll support, and I've been keeping a branch that's geared towards more simplicity on deploy (e.g. single .dll, instead of several) - OpenTelemetry's C++ solution though is more flexible, and less size used last I've tried it. Here is mine - https://github.com/malkia/opentelemetry-cpp

Where are you getting 100MB from? You don't need the whole protoc toolchain. Well I've never worked with C or C++ and gRPC, but insofar as rust, go, and python are concerned, the increase in container/binary size is a few MB.

Yeah, but you have the same problem when using Prometheus and the native histograms? So far I know it is not supported by the text / openmetrics format only in their protobuf-basaed format version

If you're using Rust, Go, C, Java, or some other performant language then it shouldn't be much. If you're using a slower scripting language like Ruby or JavaScript then you might have issues.

Just a quick clarification. OTEL is not just a transport, its a specification.