With Termux I have rsync at hand, which can compute checksums, delete files after the transfer, etc. That's why I do my complete backup with Termux. And I sort the images on the phone into dated subfolders before syncing them.

And having tools like exiftool, ffmpeg, and ImageMagick among others available in Termux is wonderful.

Yeah same in fact that's how I discovered Termux. I had an rsync.net account and thought that since rsync and ssh are so ubiquitous it should be simple to set up back-ups from my android phone. Boy was I wrong. The android apps that support rsync were all janky or suspiciously closed. Termux + rsync + Termux API's job scheduler does the trick. I think it's a bit of a drain on my phone battery but I won't complain given I own my photo back-ups from top to bottom (though I rent from rsync.net)