The most widely available concentrated source of food grade potassium is potassium hydrogen tartrate, better known as cream of tartar, widely used in baking and cooking [1]. It's about 21% potassium by mass, available in practically any grocery store, and inexpensive in bulk. So it's a great alternative to potassium supplement pills, at least for people who can do arithmetic.

If people cannot do arithmetic, they may induce hyperkalemia:

Journal of Medical Toxicology, 2013: "Life-threatening hyperkalemia from cream of tartar ingestion"

https://sci-hub.se/10.1007/s13181-012-0255-x

Case reports: In both cases, individuals ingested a large quantity of cream of tartar in an effort to "clean themselves out". They manifested similar initial symptoms (vomiting), abnormal serum potassium (>8.0 mmol/L), and EKG's with peaked T waves. Both patients were treated for hyperkalemia and recovered without complication.

[1] https://en.wikipedia.org/wiki/Potassium_bitartrate

You are wrong. I am aware of the FDA limit on pills. That's why I used potassium chloride powder instead. I don't remember the exact amount, maybe half the RDA?