This is actually doable, though you need specific classifications for each business

You can set a fee of 3% for restaurants let's say, and 10% for some other business (example)

This makes sense for small business

Amazon restaurant chain starting up, it's amazing how much of Amazon's money needs to be moved into that subsidiary.

Get a free iPhone with purchase of our $999 steak dinner.

I would assume they would raise prices so margins stay similar, though I don't know if that's been experimented with.

Even if it does mean less restaurants and less eating out, there is nothing inherently more unfair about it.

That just benefits vertical integration. Amazon would pay less taxes in Amazon basics than third party goods. What you really want is a VAT. You're only taxed on the value add of your product. It's widely regarded as the most efficient tax and the US is one of the only countries that doesn't use it.

I agree there are some issues with a revenue tax, but VAT isn't good enough because you really want to capture B2B transactions.

You can also see for example the digital services tax introduced by France because VAT was not proving effective.

VAT does capture B2B transactions. That's what makes it different from a sales tax. I'm pretty sure that you already have to pay VAT when buying online ads.

Businesses can deduct all the VAT they pay. I do have a business in the EU; I'm familiar with it.