Side note: I am relatively new here and am using the Mlem app. It seems like posting a link is done in the same way as a Reddit-style text post rather than a bare link. Did I do this right?
Mlem dev here. You can attach a link to the post directly by clicking the link button in the post editor toolbar then tapping "Paste" (with a link copied to clipboard). We're aware that this isn't the most obvious UI, and are improving the design in the next version.