It takes time. Twitter (or whatever it wants to be called) has an algorithm expressly aimed at keeping you "engaged", whereas Mastodon is just a stream of toots which you see based on the time you decide to visit. Should you stick with it, eventually two things will happen:

1. You will find accounts and topic to follow which will fill your timeline with content that is relevant and interesting to you, and, perhaps more importantly
2. Your mind will give up the habit of being hooked on a social media stream (apologies if I'm implying something that isn't true for you - it certainly was for me).

In the end, maybe you decide it's not for you, but I've been using it for years (since 2017), and over time it's completely replaced Twitter for me. I'm keeping three accounts for different interests (and one on Pixelfed), logged into all of them using Fedilab. I actually deleted my Twitter account the day the Tucker/Tate interview hit the light of day, but I stopped actively visiting it years earlier. My mental state improved a lot over time since I moved on.