If you allow taxpayers to dodge a law, the question becomes who decides when the law is applied and when it’s not and by what principle do they make that decision.

The issue is tax avoidance, not tax evasion. The law is enforced. The question is whether loopholes should be closed, and that is something the legislature can do.

As a result of the permitted pretense of making sales in country where they are not made, the MNE have a tax deduction which the local businesses do not. This increases the chance of monopoly power.

True, and it's a weight on the side of the scale for closing the loophole. But doesn't the monopoly arise from a price advantage enabled by the tax avoidance? Customers are paying less because of the loophole.

I’m not certain that there’s a direct relationship between taxation and inflation.

As the kids say on Social Media, it's complicated. But one must be very careful to avoid post hoc ergo propter hoc arguments. There is no way to assess the implications of the Trump tax cuts given the force majeure of CoVID and its economic sequellae.