It’s a little old now but a good place to start, have you seen this thread?
Interesting you are looking at protected “Panny B’s”… any particular reason you’re looking at these cells and not more modern high drain cells?
I didn’t follow the Liitokala fiasco mentioned in the link above, so I can’t confirm whether it’s the same store that @Maverick1947 linked, and/or problem persists.
For weird sized cells, I’ve ordered from the Vapcell AliExpress store, and cells have tested as advertised, so I consider them moderately reliable.