Deep labiomental fold and my chin sticks out a lot. Could a genioplasty fix this or would I need jaw surgery? (Photos)

You're on spot believing you are not a case for orthognatic surgery, at all!

You have microgenia, this is small bone developtment at the chin, therefore you need chin augmentation with bone supply (iliac grafting); not a case for sliding genioplasty giving there's no indication to slide forward, it is primery deficit of bone substance making the soft tissue hood of the chin (skin, fat and mentalis muscle) flaccid due to poor skeletal support, so you need vertical height increase plus you did not notice or mention the evident horizontal width deficit making your chin too sharp and needing also horizontal augmentation; so it's a case for a bi or tridimensional augmentation genioplasty.

I strongly recommend you refuse fillers and chin implants, taxatively, a big no, due to complications, limitations, short-livedness, etc.

Be aware of the technical experience required, do not accept miraculous "step gap" augmentations without bone grafting supply, do get reassurance of the talent and passion for genioplasties of the surgeon.

Further information and images at the link attached.