I think the big thing is that Lemmy isn't nearly as monetizable as other social media. What that means to me is that if we do grow, it'll be largely organic. It'll be at a pace where the culture won't change overnight. If we get big enough to have real issues, we can meaningfully splinter to more manageable sizes, or moderate shit stains into instances with no reach beyond themselves.
In short, so long as we maintain interoperability standards, I think we will have all the tools needed to keep things from enshittification. We might just grow out of pure longevity as other social media enterprises slowly but surely kill themselves.
But that could be wishful thinking. Who knows!
These days at least we have streaming services. If you can get them hooked on the good stuff (eg Bluey) or the tolerable stuff (eg Octonauts) you can (mostly) get away from the worst stuff (Cocomelon and it's million somehow even more cheaply made derivatives).