Other countries have solved these problems.
In the UK, most people dont have to file taxes - there are no deductions for the vast majority of people, you dont get to deduct your mortgage costs, healthcare costs or anything else. You pay your tax in monthly instalments taken from your wage by your employer, based on well known tax codes and your level of earning, and at the end of the year you get a piece of paper saying how much you paid. If you switched jobs and earned more but underpaid tax, your tax code is adjusted for the next financial year and you pay more tax per month to cover both the previous years shortfall and your new tax requirement.
If you run a business, then the business does file returns, and does have deductions - so that covers your business, Uber driver, travel expenses and everything else. People travelling for business claim expenses through the company, and the company deals with the tax implications.
A businesses accounts and the accounts of the business owner are very very strictly separate - the business owner does not get to dip into the business for their own usage, they get paid a wage or dividend, which is taxed like everyone else as income.