There are several ‘truths’ you have to hold onto. These are
We expect children to behave and be attentive in class.
To learn school stuff effectively, children need to pay attention and engage.
Disruption by one student halts the learning of all others in that class.
Disruption is draining on a teacher.
Teachers are in the classroom to teach, not fundamentally, to manage misbehaviour.
Parental involvement in schools is critical. If a child continually misbehaves, contact parents.
It does not need hard, complex work to manage away misbehaviour. We do not need complex, time-consuming-for-teachers systems!
If a teacher identifies a child as misbehaving, that child is misbehaving. Trust teachers until you are proved otherwise.
Use appropriate sanctions in a way that achieves the desirable ends.
Be determined to work at managing behaviour until the matter is resolved.
I am really happy to discuss any of these items further.