The Holy Father cannot "dispense them" from privately taken vows in an organization not under his jurisdiction, and therefore nothing he can do would remove them from office.

They are not "an Order within the church (sic)" so he can't ask them if they wish to continue being one.

For the same reason he cannot "canonically suppress the Order".

If he removes the religious, which are a minor part of the Knights, he becomes responsible for their care and feeding, including two cloistered convents hundreds of years old, and denies religious care and comfort for the many hospitals and medical centers the Knights run.

So much for your nuclear option.