I’m on a similar journey. I want to crush walnuts. I’m a desk worker, so I got a set of grip strength trainers and just use them when I’m in Zoom meetings. I can almost close a 200lb gripper after about 8 months of sustained effort. I’ve started using a light gripper to increase my thumb and pointer finger pinching strength now too. I’m going to have to see if I can squash an apple now.