A good CPA will keep you out of trouble and within the bounds of the law. There’s nothing illegal about claiming a home office deduction if your employment agreement states that you need to maintain a home office. From there, that allows one to deduct their auto expenses and other things.
But it can all add up. After retirement contributions, I usually deduct another $30-40k in expenses each year. And I’m fairly conservative, so that’s without the section 179 vehicle deduction, furniture for my home office, vacations, or fancy meals. The end result is about $2k more in my bank account each month, so yeah, it adds up.