If Twitter wants to put a stop to the user exodus and save lots of money in the process, here's what they could do:
1) Add an off switch to the for you feed. I'll click it right away and never turn it on again. Stop wasting minutes of CPU time on my behalf. I never asked for it. It doesn't do anything for me that I need or want.
2) Sort by time, filter by hashtag. Twitter used to be about real time information. I don't care about things that happened days or weeks ago. I don't need to see all of it. This is the core feature that made Twitter popular. Mastodon has it and it is absorbing users from Twitter by the millions. It still works. Restore this feature and make it the default.
3) Join the fediverse. That's where a lot of the former hard core users went. They still exist. They still post messages. They still engage with each other. They just don't use Twitter anymore. Allow people to follow mastodon users. Allow mastodon users to follow Twitter users. Not that hard to implement and probably would do wonders for user engagement.