Can not get events from slack channel

I am using node red in docker with nodered/node-red:latest image.
I am trying to use node-red-contrib-slack 2.0.0 to create a bot able to answer and/or forward messages from a slack channel.

The node slack-rtm-in should be able to detect events like a message on a channel and trigger my flow.
But I can't get it to work.

I created slack apps, current and classic, gave it appropriate OAuth authorisations, allowed incoming webhooks, and tried giving differents token to the slack-rtm-in node, starting with the Bot user Oauth token, but also user Oauth token, the verification token etc...

after all that, nothing works and I can't get the node to react to messages on the channel.

I can send messages to a channel using those same apps and token with the slack-web-out node.
But still no event on the slack-rtm-in node.

Does anyone know how to get it to work?

Thanks a lot,
Best regards,