It may well be effed up, but it's actually par for the course. Ten companies donated a million bucks to Biden's inauguration:

https://www.reuters.com/world/us/pfizer-unions-others-donate...

The money has to be spent on the event, so it doesn't go to the President's pocket or even to their campaign fund. So it's not limited the way other political donations are.

Still... Trump has a history of misusing funds, including over 30 criminal convictions, and more for his staff. If I were the FEC, I'd be keeping an eye it. But apparently everything the President does is legal, so it's probably not the effort.