pr34ch3r thank you for sharing your story.
Based on my experience, vast majority of people have their photos named something like IMG_XXXXX.jpg, since cameras and phones are naming it this way from the start. Agree, this looks little a bit better than UUID, but in fact this kind of naming is as meaningless as UUID, but it seems that most of people are OK with that.
What I see is that most people do not try to engage in difficult enterprise with renaming of all photos. Mostly what people do to organise their archive is sorting it by meaningful folder structure, add tags, fix broken dates and sometimes assign missing locations. And also add captions when needed.
The only quite common use case for renaming files I saw is just using this as an alternative for adding caption into metadata when this function is missing in the software people are using. However, caption is much better for that purpose, to my mind.
But this is just my experience. All that what I mentioned you can actually do in Tonfotos right now. And this is much easier than actually renaming all your photos.
Does this requirement for synchronising your photos with external storage puts restrictions on your ability to use folder structure? Even in that case I would argue that tags give you more freedom as you can add several tags on one photo, which is not possible in case of using directories without making duplicates. Ideally you should use both - folders and tags.
So, why don’t you consider more traditional approach?