Elon acquiring Twitter for $44B in the first place, not taking into account the subsequent blunders. He not only overpaid too much for a social media company without even understanding it, he also wrecked Tesla's stock price as investors saw he was clearly spending too much time on Twitter and he had to panic sell Tesla shares to fund his Twitter adventure. He easily wiped out hundreds of billions from Tesla's market cap during that time.
The value of "X" has been repeatedly downgraded. It's estimated at around $15b by fidelity. They've demolished their own brand by renaming themselves and how you interact.
This is before you get into the whole "twitter has been loaded with debt from the purchase of twitter and so is even more unprofitable than it was before" part of the debacle.