Hey Nader Dabit, thanks for the post!
When syndicating your content, make sure to republish posts properly and add the original URL. Hashnode and other publishing platforms support this feature which automatically adds the canonical tag to the page.
If you syndicate your content on other sites, Google will always show the version they think is most appropriate for users in each given search, which may or may not be the version you'd prefer. However, it is helpful to ensure that each site on which your content is syndicated includes a link back to your original article. Since your domain (dabit3.hashnode.dev) is fresh and not as strong as other platforms yet, your ranking can suffer.