Total user count is a vanity metric. Monthly active users is more relevant and on that we are still way off from the ATH of 2.1 million from 2023.
Also, with the nature of the Fediverse where one single person can have multiple accounts, even this metric might be bogus.
Takahe is IMO the opposite of "single user software" . It shines when you want to host multiple users with multiple different domains and identities.