That's not true. YouTube gets 45% of the money your videos generate and you get 55%. If a viewer buys a YouTube subscription then 55% of the price of that subscription gets shared among the channels that the viewer watches.
Subscriptions are not the same as Premium. Paying for YouTube Premium basically does nothing to help creators, so you have the extra layer of Subscriptions to individual channels and YouTube get you twice by expecting you to ALSO pay for Subscriptions.
No, YouTube premium revenue is also shared to the creator. As a creator you even get a breakdown of how much you earned from ads and how much from YouTube premium.
I actually forgot that YouTube had rolled out the Join button. You get 70% of the revenue of the Channel Membership (join button). YouTube gets 30%.