Its simple if your are an employee and complex if you are an employer. For the self employed there is a super simple filling up to a certain threshold. Companies also have additional requirements based on revenue brackets, number of employees and type of economic activities they do. Anything sligth complex eill require multiple agencies fees and byzanthine laws.

There's a lot of players involved. IMO for regular people it's simple/cheap, but for companies/employers it's complex/expensive

Federal government charges taxes on income, production, import/export and over bank operations; states charge consumption and vehicle taxes; cities charge service and property taxes. Then there's also contributions that employers pay for workers, and some that workers pay.

However, consumption tax can compound itself (because of sales between distributors, or taxes over raw materials), so there's a "substitution" formula which can get pretty weird (but companies take care of it).