Picture Book Reader Magnets?!

Is it ever a good idea to use a picture book text- only manuscript, with only an illustrated-AI- generated cover, as a reader magnet?

I have 4 manuscripts in a series that are still completely unpublished. They're set on the fantastical Island of Splight, with clear thematic connection and a consistent rhyming style, so they definitely belong together. I really want to work at building my email list with a better reader magnet, to build hype for this series. I'm leaning toward indie at this point.

I'm currently using a reader magnet story with completely different characters, for a younger audience, and I've gotten 157 subscribers so far, using that. I also have another story, written with similar rhyme style and theme aligning with the Splightian stories, but far less Imaginative, and not directly connected in any way, that I haven't shared anywhere. Then there's a Christmas story, written in prose, with a much more direct spiritual lesson.

I know I need a better reader magnet, and I'm leaning toward sharing the text of the first Splightian book, if that's ever a smart approach. I've seen this done at least once before, but I'm wondering what the pros and cons are. I'm suspicious a trad publisher would never publish a story that's been seen before, but I'm leaning indie anyway. Are there any other downsides I'm not thinking of? I feel like I don't know how to create anything valuable to share from that world that doesn't end up becoming a full story! And I really think the best way for people to get excited about the books is to get a sense of the tone, the rhythm, and where on the scale of entertaining vs preachy they are.

But where could I even promote a children's story that's text and cover only? I've never used Story Origin or Book Funnel because I'm unsure about this. I don't want to spend money to promote something that doesn't deliver on reader expectations when it comes to illustrations!

I've dabbled in AI image generating enough to confidently decide I don't have enough time to figure out how to do great and consistent pictures myself, for fantasy creatures and with the technology that exists now. Is the only option to pay thousands to illustrate a story I give away for free?

If any of you can share what kind of reader magnets you've used to grow an audience of picture book fans, I'd love to hear it! Leave a link below, I'd live to check it out! :)

I should add, I really feel like my writing is my best asset to parents and potential readers. I don't homeschool, I don't create recipes anymore, I'm just a tired mom, lol, and I I'm not a guru of anything except for weird, irrelevant niche things, so I don't have a parallel following of any sort that I can lean into.

Also, the age- old suggestions just don't cut it, Imo. I mean, a coloring page, or a lesson discussion, without a story to teach the lesson? Yeah, right! And furthermore, I don't have any illustrations to create coloring pages from.

So, thank you heaps and piles to anyone who can help sort out my predicament!