The Anglican Communion is essentially a federation of national and regional Anglican churches (called “provinces”). You should think of it in terms of the United Nations. The US and Russia are both members of the UN, but they are completely different countries with their own laws and rules.
In terms of the Church of England, yes, the Archbishop is the “Primate of All England.” However, his authority outside of the Province and Diocese of Canterbury is limited. He’s not like the Pope. CofE bishops have a lot of influence within their dioceses.
Plus, Canterbury is not the only Archbishop in England. The Archbishop of York is primate of the province of York (in northern England). So, outside of the province of Canterbury (in southern England) the Archbishop of Canterbury’s powers are even more limited.
The ultimate authority in the Church of England that all bishops are ultimately answerable to is the General Synod. This is a representative body made up of bishops, lower clergy, and lay deputies. They make the Church of England’s rules.