Even though she is as much of an Atheist as the rest of us, her mother is a devout Catholic, and she doesn't want to upset her at age 94. The Solidaritätszuschlag still shows up on my German tax return at around 5%, and the current max tax is 42%. Added up, it borders on 50%. Plus, I have no pension here, and no health insurance. The government only takes from me, gives nothing back. I have a German friend here who started his own business close to 50 years ago. He is still active, and he had his accountant calculate out at what point during the year he stopped working for the government, and started working for himself. The date was sometime in late September.
If the Soli was changed in 2021, I won't hear about it until the end of next year, when the return for 2020 is due. My income is solely in the USA, but taxed in both countries. The Doppelbesteuerungsabkommen, according to both an expert in the field and a neighbor, who is both a judge on the Finanzgericht zu Düsseldorf, sort of the State tax court, as well as a professor on taxation at the University of Bonn, has plenty of holes where an individual can be hit for taxes on the same income in both countries, and end up paying as much as 70% or more on the US income, depending on its form. He wrote his doctorate on double taxation. Our neighbor knows German taxation better than just about anyone, and if he says I'm screwed, then I can pretty much take it that I am. It is his job to know what a taxpayer resident in Germany can get away with and what he can't.