Cooking vs Soaking Lentils for Falafel
If you want to make &quot;falafel&quot; out of lentils, then you should look to folks who actually make deep-fried lentil balls regularly, and that's Indians.  Dal Vada, balls of lentils that are deep fried in vegetable oil, are always made with lentils of some kind that have been soaked by not cooked.  Cooked lentils, like cooked peas, will not hold together.
My suggestion is that you look through the various dal vada recipes online, and change the spicing on them to match falafel spices (cumin, onion, garlic, parsley, and Aleppo pepper).
However, one thing to notice is that most recipes use chana dal (black chickpeas), moong dal (mung beans), or black-eyed peas. So it may still be the case that trying to get patties to hold together using grey/red lentils is very difficult, even if you don't cook them.