Uh, the first one. It’s all downhill after that. It’s the only one he’s ever pulled off. Look at the goals for the master plan part 2 and you’ll see that they haven’t managed to do a single one, but Elon still went ahead a published a part 3. Why actually meet goals when you can just pretend you’ve met them by posting new ones, I guess.
trademarks are good for 10 years and looking at some of twitters trademarks it seems the renewed them in 2019. So yes, in 2029, if X hasn’t reverted to being called twitter then their trademarks will be unprotected.