Hackamores are the strongest bitless bridle you can go for. Anyone riding in them must be an advanced rider with good hands.
Also I’m in Australia and hackamores might be a bit different over here haha
A strong hackamore opposed to a regular one to me would be the strong one not having a chain cover so when pressure is applied on the reins they will feel the chain rather then just a piece of leather. Sorry if that didn’t make sense
As said anything can be strong in the wrong hands but it depends what your horse responds to more if he/she responds better to poll, nose, chin pressure better that lips, bars roof of mouth plus the others mentioned then hacksmores would be maybe a better option but personally I think hackamores are just as bad as boys as the pressure is not taken of unlike a bit if it’s too painful the horse can open it’s mouth if it does t have a flash so yes hackamores can be similar to bits.
Hope this helps
anything can be strong or harsh in the wrong hands