

In which language, English? Though why would renaming them in English require the approval of everyone in the world?
I’d say you don’t even need the approval of everyone living in an English-speaking country. It’s not like the US and UK use all the same words, for example. I think it’s fine for one English country to unilaterally rename them, no need for wider approval.
FediDB says there’s 966885 active users on the fediverse in general, with 47.8K being Lemmy users.
Though this is usually measured as monthly active users iirc, so not exactly accurate to the daily you requested.
You can also get the value of any given instance’s monthly active users by checking their nodeinfo endpoint. Here’s the one for your instance. But again, that’s monthly, not daily.