In prior financial disclosures Flynn failed to include payments from Russia to spread fake stories from Russian intelligence. He has since amended his financial statements.

Flynn was bought off cheap. $45,000 for a speech in Russia praising Putin.
Also 5 figure payments for services he performed while in America. Manifort (ran Trump Campaign) got 10 million a year from Russia for at least 3 years.

This is only what is proven and admitted so far.

Was Trump himself paid? We have not proven that yet. However there is a ton of circumstantial evidence. We believe we know how he was paid.
We believe he was paid by being the leading figure in a consortium to invest in buying 19% of the only Russian Oil Company which would open 63 million sq. miles of drilling rights to Exxon - only if sanctions re dropped ginst Russia..

In comparison Exxon has the oil drilling rights in the USA of 14 million miles.

Trump is an opportunist who will take money from anyone. Russian oligarchs are a mixture of crime bosses, oil company, money laundering organizations and government officials. We know Donald has a huge debt to known money laundering Banks in Germany and Cyprus.

A tax return may be a short cut to prosecution for Donald but there are other ways.