Other slack community are very strictly against it in the CoC. I just double clicked the bookmark link https://github.com/InternalDeveloperPlatform/Platform-Engineering-Community/blob/main/COMMUNITY_GUIDELINES.md above and found:

The basic rules for the Slack channel in regards to promotion and product are:

• Things you can do: Post links to your own website/product, promote your talks, promote your meetups, connect with others in the allocated spaces as specified below.

• Things you can't do: Only post self-promotional posts/comments; send unsolicited private messages to members about your self-promotional content; use redirects to obfuscate your self-promotional content.

The second bullet specifically calls it out as against the rules.