Squatting and deadlifting is plenty.
Directly training the obliques is a god awful idea for any non high level athlete. I dont care how skinny somoene is, there is no reason to make your waist thicker on purpose unless youre a budding SHW powerlifter.
And about the side bends. Dumb. Your obliques wrap around your midsection, they dont go “up and down”. Usign 2 weights is even more dumb. What other exercise can you think of that uses a counterweight? None.
If you want to train your core completely you do three things. A crunch type movement where you bring your torso towards your lower body. A leg lift type motion where you bring your legs toward your upper body (knees bent for better ab recruitment). A twisting motion to get the muscles underneath the rectus abdominis, russian twist on a decline bench works well. Adding something like dragon flags (properly done with your ass off the bench) is not a bad idea either.