You can almost achieve this by setting a reminder to turn on "sync immediately" manually every single day (because Apple decided there should be no permanent or indefinite option, and went through the extra effort of making it timed simply for the sake of inconvenience).

I actually do this because it's the behavior I've wanted for years, and I care about it enough to go through the relentless annoyance.

I just don't understand why they wouldn't enable something p2p. We have handoff, screen mirroring, etc, but simple photo sync is impossible scientifically.