Ament Build -test failed

According to the test results pretty much every pub / sub is failing for you for both rmw impl. That is certainly not supposed to happen and something severe seems to be wrong on your system.

Can you please try to run the tests for a single package (e.g. demo_nodes_cpp) and check the output for why those fail. I expect a generic error in the invocation of the tests since the talker seems to work just fine for you.