I have followed this topic with interest. My need is related. I use obsidian, with obsidian sync on a PC, iPad and iPhone. Storage size is the killer for me on my mobiles, as my vault is now over 10Gb as is now the largest app on my mobiles. A web version would instantly solve this, even if it was read only. I would be happy enough to store anything new while mobile on Simplenote and transfer it manually when at my pc.
However as most of the size of the data is in the _resources folder, it would solve my problem if I could at least have obsidian store _resources in cloud storage.