I think the simplest way forward would be to require immediate, not delayed, disclosure of trades. If they’re doing something, let everyone see it immediately and it specific detail.
We could also implement some planned trading requirements for large purchases of individual stocks: If someone wants to trade more than $100K of something, make them announce it 7 or even 1 day in advance. They still get to buy it, but the market can front-run the investment if they believe there’s inside info at play.