I realize this is a dumb question, but what's a good way to do this between an iPhone and a MacBook? Airdrop is disabled (by policy), iCloud storage is full (because I'm lazy), and I use syncthing on every other device, but I haven't found a client I can use on my work iPhone.
I've been using sharedrop.io which also is open-source [1] and it works quite nice, I particularly like this one because I don't have to install any third-party app on any of the devices.
I think on mac Safari usually doesn't work as well as in Chrome, but I've been able to transfer from Windows to iOS, Windows to macOS and macOS to iOS without installing a thing.
I like LocalSend and Landrop. The latter performed better when I sent large files. However, neither of them does it automatically; you have to manually do it every time, which is okay since they don’t claim to be sync software.
When python is not installed already (Windows pretty much) or the computer is the destination, I prefer https://github.com/sigoden/dufs, a single binary supporting uploads, folder .zip download, and even webdav
Signal 'note to self' works. I have several nts's...medical, links only, shopping...if I think of something on one device (pc/ android for me), it's on the other within seconds.
I tend to message myself a lot of things. Usually links not files, but it works and it doesn’t take me out of the headspace I’m occupying. Either Apple messages or slack.
Möbius Sync doesn't sync in the background; you must have the app in the foreground for it to function. So, not quite a proper substitute for Syncthing, but may work for OPs usecase.
Right, it does the best it can given the limitations of iOS, but "not instantaneous" can mean hours before synchronisation happens. When the phone's charging, or when the app is open, then it does tend to work almost as well as on Android.