LOL..."considerably less appearances"? WTF? Uh...did you not just see the Clinton's launched a global speaking tour that went down in flames because nobody wanted to go? The tickets had to be sold on Groupon, and even then nobody would buy them. By 2019, The Clinton Foundation had fired 90% of it's staff because no money was coming in.
"Investigate Hillary 7 more times"? Now you're conflating the investigation around her government job with her foundation. The foundation, as far as I have read, was never investigated by the State of NY like Trump's foundation was.
And yes, when you file your taxes, the government reviews them for irregularities or anomalies. This is what triggers investigations or audits. So because you have never seen Trump's returns, doesn't prove illegality. Also, he is not required to release his returns by law. It's completely voluntary.