I found potassium tablets about the most I could do was 3x99mg with meals.
Using potassium ascorbate (vit C bound to potassium_ I do about 4x 1/2 tsp per day. 1 slightly rouned teaspoon is 4000mg ascorbate and 700mg potassium and I do that empty stomach with no issues so thats about 350mg potassium.
Ive also got some potassium bicarbonate 1/4 tsp is like 390mg, can use that at 1/4 alone or with 1/2 tsp of potassium ascobate (would be about 750mg potassium) together with food or empty stomach with no issues.
dont get too disheartened its very rare a sngle or even a few elements will solve all your problems. Nutrients are too tightly interwoven and it takes slowly adding them and tweaking doses over months to get things dialed in but in the end its well worth it.