I’ve been trying to work on something similar for !ebookdeals@literature.cafe posts. Though I’m going a bit more simple and trying to just generate the text I can use for the post title and body, then pasting them in myself.

I don’t think you can do this yet, none of the lemmy apps I have installed show up under the applications tab in shortcuts.

It may also be too complicated… it’s easy to set a shortcut to post to Mastodon, but that’s because when you post, it’s always to your own account, as opposed to Lemmy where you have to choose a community to post in.