what is the meaning of this ? do i need to shrink my app?
You should click the “Learn more” link to see if it provides more info. Otherwise you will need to contact Google for more details.
Nothing in your screenshot says anything about app size, however.
can i publish it with that warning?
My recommendations were for you to pull up the learn more page and read it so you could understand more, not post it here
GDevelop doesn’t own or have control over the app stores, so the folks here are unlikely to be able to provide guidance on errrors and warnings being given by the stores.