Then, I’d say that checking every tick is a cost you have to pay for your experience, since the change of day is core in your game (and not linear). I mean, Tick functions exist because in rare/specific cases, if you really cannot find any other alternative, you should use them.
Remember that you can adjust the Tick frequency, and consider making a small C++ function very simple that performs this check for you, even if the rest of the project is in Blueprint.
If you give me your current code, I could try to convert it to C++ for you.