Picture & file storage service recommendation

Hi everyone, I'm hoping to get some recommendation for services that would fit my needs.

Needs

95% of the files will be photo taken by Retool mobile app, 5% of the file will be PDF. Maybe odd doc or excel or csv. It's ok if PDF + Img only

All my users will be in Australia so CDN is not critical, but this is based on the assumption that both in mobile and web version of retool app, the image is fetched by the client, not by retool server in AWS-WEST

Some sort of image processing is needed for serving thumbnails and small size previews.

Strong preference to have multi-level folders and API for them, so that we can better organise the files.

Preferably when serving image, using API key or similar instead of one time url. This is to reduce the code/query in retool app while still keep the files private.

Preferably a relative simple package, rather than S3 + this + that...

we'd be generating 15-30 photos a day, so in a year, there would be about 10K files, 3-10G of files depending on format stored.

and on the wish list, off-shelf sync to Google Drive or One Drive etc, we can always code this manually.

What I found so far

S3 cost next to nothing to store few GB of files, but image compression for storage and resizing all require extra code or services. Not completely against that, but I also have other things to better invest my time.

Cloudflare Images, cost $5/100K image, built in image compression and resizing. But it doesn't support folder, nor PDF files. And doesn't support using API-key to access files.

I haven't tried google drive integration, did find a tutorial, but doubt if image compression and resizing would be possible at all with it.

Last thing I thought about is maybe self host some image service or self host retool and use built in storage function without the 5G limitation

Thanks in advance for any recommendations.