YouTube Shorts For Easy Initital Growth and Swapping to Long Form Content From Short Form?

So I have a business channel with around 20 subs, I decided to just post my Tiktoks that I already make as shorts there. I have noticed the channel performs really well with shorts but I am curious, will posting only shorts mean when I eventually do longer videos that they will also perform well or are they likely to do poorly with the subscribers expecting short form content? Has anyone got any experience with growing a channel at the start solely off shorts.