Why are you fixated on Marxist progressive tax rates instead of the actual taxes someone pays?
Loopholes is an interesting and misleading word. Those "loopholes" are actually parts of the tax code that politicians, under intense pressure from special interest lobbyists, voted for. Another bipartisan effort.
The lowered corporate tax rate (which includes taxes now on repatriated overseas income) has raised more in tax revenue than projected under the old corporate tax rates. Raising it a few percentage points would not result in much additional revenue but could result in lower revenues due to the laws of economics. Also, their is the competitive effect of lower corporate tax rates around the world. As of 2022, the US has the 81st highest tax rate out of 225 countries.