@takkix I just buy potassium citrate powder and take 5 to 6 grams which equates roughly to 4 to 5 g that actually get into my system (maybe a bit less).
If you
don't wanna go that route (which isn't a bad one). I would recommend you actually eat raw vegetables (spinach is actually one of the bests, props to you) as cooking any veggies will significantly lower the potassium intake. Most of it is gonna be lost and goes down the water (inevitable with heat, so make soupes or something) even with vapor cooking.
Add to that some Magnesium (1.5 to 2 grams) and you should hopefully see an improvement.
Avoid using salt with potassium rich foods as they will hinder each other.
If you gonna use salt, please use actual salt, not the trashy ass shit that they sell now in supermarkets that is "half" the sodium and comes with very low bioavaillability potassium and other stuff that is only gonna damage your kidneys in the long run.
Last tip, don't drink tap water, get some quality water that has very low minerals (they are not bioavaliable anyways, high price doesn't equal high quality). Get your minerals from your veggies/supplements.
Sorry this was long.