I play Shattered Pixel on my phone, and sometimes circumstances cause a mistap or similar, and with the way this game works a single bad action can mean a drastic hinderance on the run or effectively ruin large amounts of effort.
This is true for many games, and in most circumstances I can roll back to the last save and lessen the loss. While in plenty of others I can edit the save files with a shizuku-powered file manager. I had hoped that the non-google android version on github would expose the save files to shizuku, but sadly learned that was not the case. Of course, there are others where neither are an option and I just have to live with it, but I just tend to not play those games for long or that much. However, I've been playing Shattered Pixel for years. It's easily the one mobile game I have spent the most time playing. But it can really kill my desire to play for long periods of time when something happens to kill a run I was really enjoying and spent a good amount of time on and there is no way to "undo" any amount of the loss.
For me, it would be an absolute game-changer if there was some way to allow manual save/loading or access to the save files. If it means by an opt-out of online leaderboards or whatever I'm okay with that. (I'm not sure what there is for SPD, I really don't know because I only care about offline regular play.) You can mark my game a "filthy gross evil stinky dirty cheater" or something, I don't care. Personally, I don't consider it "cheating" to recoup from a mishap outside of their control in an offline singler-player game.
Is the threat of some sort of bad-actor that high that save/reload or save file access can't be considered? What exactly would be on the line by allowing "cheating"?
I have to imagine there would be a sizable enough group of people interested in manual save/load or save file access considering there are save editor tools out there, like spud. It would also allow easier transfer of game progression like this request mentions.
Is manual save/reload something that would interest others that you know of? At least, enough to get 00-Evan to consider some sort of option? Can we work out some sort of option that 00-Evan would consider?

I also want to note that I went out of my way to make this post after having left lemmy due to far too many awful experiences on lemmy. I've been significantly happier not using lemmy, so I feel like I am really out on a limb just to make this post.
I don't know about how cureent mods are but there used to be one which had save slots you could copy and back up. It was a fairly large mod and took Pixel Dungeon in a fairly different direction with you starting in a town and being able to return through a portal every few levels. It was cool but doesn't solve your issue.
Could you back up the entire game data? Maybe that would do the trick?