I think what he's generally saying: aggressively deduct expenses used to support your business. This would include rent, home office, computers, phones to conduct business, business meetings, travel, health insurance, retirement, etc. Then the member and spouse would draw low salaries putting you in low income bracket and thus low taxation. The 2017 TCJA further reduced taxation for business owners via the Qualified Business Income (QBI 20%) deduction.
I suspect a large part of it is a SEP IRA which lets you pack away like 57k in a tax advantaged account. Business deductions are almost like icing on the cake vs that.
Deductions sound good to people who haven't actually run a business or thought very hard about it. You have to be purchasing stuff to deduct. As a software engineer why not just not buy stuff since all you really need is a computer. Then you keep 100% of that money rather than 10%.
Some outliers are home office and utilities and things like that.
The attraction of deductions for sole proprietors working from home is not buying new stuff, it is the opportunity to pay for stuff you would buy anyway with pre-tax dollars.
The IRS has rules (typically unenforced) regarding this. You are supposed to draw a salary that matches your job in your local area. So if you are based in Tinyton, Flyover State, you could probably get away with paying yourself $30k/yr, but in NYC (where I'm based), my accountant told me $70/hr is basically as low as I can safely go. So I do $70/hr and then $14/hr in my retirement account.
The $70 turns into ~$78 after all the employer taxes add into it, and I take home only $52 after employee side of taxes are taken out of it.
In lots of countries you definitely can't deduct rent, non-business travel, health insurance, or retirement. And home office only if you have a dedicated room for it.
I'm freelancing currently myself, and available deductions are honestly miniscule and well-defined.
