Hi Ruth,
Yes — it’s a rabbit hole out there!
For your book, I can recommend The Book Proposal Masterclass by Beth Kempton.
This is a month long, on line program where you get to meet and talk to agents and publishers.
It’s really intensive and sorts the sheep from the goats. If you make it through, you probably have a publisher and complete life change at the end.
I’m not great with links — just google the name and you will find it. I think the next one is next spring.
Good luck,
Nicola