How do you handle sibling conflict during lessons?

Separate physically even when on the same subject. One at the table, one at a desk in another room. Same lesson, zero eye contact.

Clear individual roles. The older is never correcting the younger during lesson time. Enforcing this changed the dynamic.

Competitive subjects separately, collaborative projects together. Maths separately - different levels, no comparison.

Morning basket works because there is nothing to compete about. Keep the shared time creative, not evaluative.