Is there a way where I can create a forum section just mainly for spams? I don't want the post counts to increase for the members who posted there.

Also, is there a way to remove ALL the posts of a member? It's tough job deleting one by one.

Its currently not possible. However, its been suggested.
https://help.forumotion.com/suggestions-for-your-forums-f30/no-post-count-disabling-post-count-on-a-particular-forum-t5848.htm