AGONY: Home has become a 'battlefield'

My husband and I, have always disagreed on a number of things for the last nine years. However, last week, when we started working from home to avoid the spread of COVID-19, things got worse. 

We are fighting about everything, from who uses the laptop charger first, what to have for lunch, who is giving the children work to which channel we should watch. 

This is so draining and stressful. What should we do to live in harmony as we share this small space?