I agree he's probably regretting it. I suspect he's going to try to make Twitter more profitable as fast as possible and then maybe sell it when it's on its way to being good. It's a distraction from things he cares about more, but it's not unimportant.
Musk got bullied into buying Twitter by a bunch of WallStreetBets folks, took a puff and tweeted out a number, and surprise surprise, the offer was accepted. And then he’s been struggling to get out of it ever since