Sorry to say but Mastodon was always a failure because the “global” feed literally never worked. By design it has network effects working against it, rather than for it.

I used it for barely a few weeks before I found I couldn’t find anybody I was looking for, was trapped in a very small echo chamber, and had to make a totally different account when I was on a different instance at one point, and I just threw my hands up at that point.

I can’t see how it can ever actually have the momentum necessary to become a scale that matters. And honestly at this point the opportunity is already passed.