I have used Content Type Hub in On Premises and haven't had much issues but with online it's very difficult to use.
What I am seeing is, when we create a new site content type doesn't show up immediately but it takes hours.
We have a multi GEO and with Satellite location it takes more time compare to Default/Main tenant to get the content type to be available. Sometime it takes days(2-5 days).
I would really appreciate if someone can help if this can be speed up.