If possible, soak cashews two days before in the fridge. An overnight soak or a quick-soak with a five minute boil will do in a pinch. Drain & rinse. Add to blender with the filtered water and process until very smooth. About 2 minutes. Different blenders may require a bit more water. That's fine, just add in small amounts until it blends easily without getting too slushy and splashy.
Take the lid off the blender and add tapioca starch, lactic acid or lemon juice, salt, nutritional yeast, paprika, and oil. Process another minute or so, scraping down the sides if needed.
In a food processor or with a sharp knife, shred jackfruit. I find I don't need to discard anything if I use the food processor, but if you're doing it by hand you may prefer the texture without the stems and seeds. If using a food processor, pulse until the texture is evenly flaked.
Heat a large pot on medium, and pour in the blender mixture. Stir on medium to medium low with a heat safe rubber spatula, until it begins to stretch and come together. About 8 minutes. You can add more tapioca to speed it up, but I prefer the texture from going low and slow.
Once stretchy, turn off heat. Fold in jackfruit & vegan mayonnaise, if desired.