Pilsner is not an easy beer to brew with one exception: the water. Add 1/2 to 1 tsp (2.5 - 5 grams) calcium chloride to each 5 gallons of RO water treated and that's it. You neither need nor want any bicarbonate for Pilsner beer. You can dilute your tap water with RO if you really want to but 1:1 isn't enough of a dilution as it leaves the sulfate marginally high.
With respect to the acid malt: add 2-3% of the weight of the grist. That will bring pH into the right range.
With respect to the acid malt: add 2-3% of the weight of the grist. That will bring pH into the right range.