I have a similar intersection near me. It’s at the bottom of a hill, and there’s pretty regular traffic at a stop sign on my “NN” before they can continue west on “N” (to go northeast on N there is a separate little turn off of NN with its own stop).
Coming down the hill, it’s customary to use a turn signal either way. It allows drivers waiting to go west on N to understand the intentions of oncoming traffic.
If you live where I live, there’s a 50% chance you’re not using signal regardless of the road configuration…well at least that’s how 50% of the population here treats using a signal.
Signal? SIGNAL? And telegraph our punch to the enemy? Fuggeddaboudit!
And if you live where I live, there’s a 50% chance that the other 50% percent have their turn signal on all the time!
Where I live cars at a light on a side street going into the main street who are turning left signal only when the light changes, not just before so cars in the other direction know they are turning and not going straight. They must think that the wheel doesn’t work if the signal is not on. Drives me crazy.
As for the OP, I was for signalling from the map - the streetview made it clear you should signal.
That is the sort of thing where I would give a courtesy couple of blinks and go. Not required but why not.