[mothered]

cannt guess it is the problem of new blogger or what..

The new Blogger theme has no Impact on the Issue you're experiencing.

I've just created another social engineering blog (with a top-level domain name) using the new theme, and It's perfectly fine.

image of page main number : https://imgur.com/a/fiuSF63

I'm not referring to the posts set In Blogger Itself, but rather the numbered pagination that's either In the HTML/JavaScript gadget or the HTML template.