Your completely correct but Google also tells me that, at least in the case of Uber, it will calculate the tax for the ride and you just have to report it to the government at the end of the month. Also there are some really cheap accountants you can use over here and I’m sure they exist overseas as well, but I suppose I don’t know OP’s financial situation and neither of these are free.

In Australia my employer reports my income and does all the tax before I get paid. Then at tax time I go to the Aus tax office website; review it, add any claims I want to make and submit it.

This is an American solution to an American problem.