If I want to buy/sell Boeing stock and I'm a Senator, I should have to publicly file that intention three months in advance, and not be able to undo it. Those filings should immediately be public in a data feed.
I'd expect to see a "Congressional stock purchases index fund" arise, and it'd be fascinating to see how it performed.
Stuff like https://www.cnn.com/2021/08/11/politics/rand-paul-wife-stock... - "oops, forgot to disclose my stock moves for over a year!" - should be punishable by loss of trading ability and confiscation of the assets (not just profits) involved.