Smith very much supported the existence of the state for several purposes. If I recall correctly they are things pretty non controversial like defense, infrastructure, property rights, regulations that enable markets to operate effectively (providing necessary transparency so that people can make informed choices, protections against monopolies and rent seeking behavior). He correctly identifies that while some regulations are necessary, some will seek to use them to protect their own position, ie regulatory capture.

Overall, his message is decidedly pro freedom and against top down economic planning and intervention. People are naturally self interested, and enabling them to voluntarily trade with others as they see fit enhances the life of each partner of the trade. Scale that up and society advances itself with an centralized arbiter to guide it.

As for taxes, the reason he felt that the rich should pay more is because they derive the most benefit from the existence of the state.