As I read the #Twitter rule on platform promotion, it's still a violation to highlight an account on your own instance, even if yours isn't specifically listed on their website.
With language like "such as" I don't believe their list was intended to be exhaustive.
Other language doesn't reference their list at all: "Accounts that are used for the main purpose of promoting content on another social platform may be suspended."
Just be aware that hosting your own is not a solid workaround to avoid violation. It's still promoting a 3rd-party platform.
https://help.twitter.com/en/rules-and-policies/social-platforms-policy