He don't own any DOGE in his wallet and although he has tweeted about this coin, he hasn't recommended it to anyone or claimed that it is a good coin to invest in.
No one can confirm that Elon didn't buy DOGE before. Creating a DOGE wallet is very easy and we don't need KYC to be able to start storing and transacting with DOGE. Everyone has something that is not known to the public, they let it be a private secret and of course for personal gain, whether it's privacy or some other conspiracy, we don't know.
What we know right now is that Elon Musk's power is strong enough in the cryptocurrency space to manipulate the market for some cheap coins or coins of moderate volume. If we consider this a nuisance and think about it over and over, I think I'm running out of time to maximize opportunities in other cryptocurrencies