MEYAGO 5PCS Crochet Hook Grips Set Ergonomic Crochet Hook Handle Multi-Size Ergonomic Crochet Hook Handle Attachment - Fits 2mm to 10mm Hooks

PT/OT here. You are hyperextending the fuck out of your thumb. I would guess that you have some hypermobility things going on, and judging by the crutches in the back of your video, maybe some EDS? Or you just frequently sprain things/fall a lot? Somebody recommended hand therapy and I could not agree more. They will size you for an oval eight ring, and that will help prevent the hyper extension. I would also look into the thicker handled crochet hooks. There's one that has interchangeable hooks but the handle size stays the same . There are also cheap handles that go over your hooks to build them up. There's a variety of ergonomic hooks that can help you out as well. Good luck!