Body weight resistance exercises pointless or not?

not pointless.. there's all kinds of things you can do with body weight. i also lift heavy and although BW squats are going to cut it for me, push ups still do. especially if you're making your variations harder like dive bombers, feet elevated, diamond push ups

The resistance with bodyweight comes from the amount of torque you apply to joints. By decreasing the leverage of that joint you can apply a massive amount of torque.

Planks and crunches are pointless. Well planks are useful for building endurance, but they are way too easy to be a useful strength exercise.

But pushups are useful and heavily modifiable to extremely difficult variants such as 90 degree pushups, true planche pushups. Things like one arm pushups require an intermediate strength level to perform, and they too can be modified by elevating the feet.

For legs for high resistance you can do pistol squats (jumping pistols if a standard pistol is too easy), shrimp squats (also can be done explosively), and glute ham raises. The opposite of a glute ham raise, a bodyweight leg extension, is also possible to perform.

The point is to work and move your muscles with controlled and proper form with or without weights. Go easy on your joints and go slow and focused on each movement you do. Body weight workouts are NOT pointless and neither is the plank or crunches. They're only pointless if they cause discomfort that you're not suppose to be feeling like in your back or joints. If you can go them with all you have without discomfort, it is not pointless. If you're not strong enough to do them yet, do something else that works the same area to build up your strength and them incorporate them into your workouts. And yes, protein is important, even after cardio in my opinion - to protect your muscles from breaking down. A certain amount if cardio mixed with not enough protein can make them shrink.