Given that your water is very high in temporary hardness (low sulfate and chloride compared to Ca, Mg and alkalinity) it should also respond very well to alkalinity reduction by boiling or lime treatment. The latter is used by many breweries but a bit more involved. Okay, now you lost me (I think). Does this mean that I could boil my strike water (and then let it cool to the correct temp) and that would help also? Would this mean that I would need less RO or lactic acid?
I don't want to overload you with water stuff so we won't discuss the lime treatment.
But when you boil your tap water you'll notice that you get a white precipitate (haze) which settles when the water stops boiling. That haze is actually calcium carbonate or chalk. And when in comes out of solution it takes some of the water's alkalinity and calcium with it. The remaining water will therefore be less alkaline and have less calcium in it. To what extend I don't know. But you'll have to rack the boiled water off the sediment to get the full benefit.
Although brewers may have done that a long time ago to soften alkaline water it has now been abandoned due to the high energy cost and because the addition of lime can do the same.
Dillution and/or acid should be your first approach for now. Once you get more comfortable with water threatment you may come back to the other techniques.