SMB (the protocol) works across devices and OS's, and I use SMBSync2 to dump my photos to my NAS + off site
https://files.catbox.moe/rpqu4h.jpg
This has worked fine for me for years even thou the app isn't on the Play Store anymore, and is fairly granular in regards to file types and where you wanna back them up
Nah, more like a better WhatsApp but with haters even worse than the WhatsApp haters.