Yes, they should, because I _need_ good feedback for connection issues.
I have not used those two specific apps, but for other "online first" apps it's such a common problem. Open an app, type a note, switch back to a different app (or turn off your phone, or close laptop lid).
Later on, you want to access the note and it's not there. Why? the authors decided to be "smart" and "offline first" and made sync in background, with no feedback, or with heavily delayed feedback... and I was walking out of wifi range when i was typing the note, so connection was spotty.
The OP's demo TODO app has exactly the same problem - no indication when the data is already uploaded. So please, if your real goal is collaboration, let user know when you cannot perform it, don't sweep it under the rug hoping the things would get uploaded eventually.