How do shorts work in long term?

I plan to use Shorts to blow a channel up and then promote my main channel, however, I've been posting Shorts at the hours which have shown me the best results, Getting a good 20-30k views every time I do that on a new channel, but whenever I upload shorts at the same time on my other shorts channel it gets barely any views (1-3 at most)??

Does anyone know if this is a shadowban or such?

check your stats on social blade - and you will know if your banned by your stats

https://socialblade.com/