icloud folders for photos created on PC do not appear on phone

I have an iPhone and an iPad but no Mac. So I've been using iCloud on my PC to try to organize my photos. I've created folders and subfolders and placed photos where I want them. Working exactly how I would expect so far under iCloud on my PC.

I go to my iPhone, open photos, and I see the folders and sub folders I created on my PC, but they do not contain any photos. I thought, maybe it needs a while to update/upload, but the next day still nothing. I tried turning off iCloud photos on the iPhone and turning it back on, nothing.

I suppose that since the folders are showing up, I could manually "move" photos into those folders, and repeat the process for each device. But it is much easier to move the photos around using iCloud on the PC, and there are 1000s of photos. Plus it seems to me that having to repeat this on each device would defeat the entire purpose of using iCloud and having all my devices signed in.

So in the end, the only thing I have succeeded in doing is creating empty folders (except they're not empty on the PC).

Please tell me there is something simple I am missing.