IOS across devices - only with webdav

Things I have tried

What I’m trying to do

I would like to use obsidian very much. so this is my first post.
But the main point for me is, to sync one vault across 1 iphone, 1 ipad and 1 mac only with webdav.
I read a lot … and it seems, that there is no solution.
Am i right?

Does anybody else found already a solution for this usecase?
Thank you very much for your time!

regards - axel