Hello Sonia,
At the moment I do not think that what you are trying to achieve is possible using standard procedures. Only thing wee could think of is actually just using multiple Collections ( 3 at your case) where you would make one paginated with 3 items per page, another one with 2 and final with only 1 per page and based on viewport show only one that you want while hiding the other two. However this might not be the most optimal solution since that will make your website show a bit slower speeds on Page Speed Tests.
Also a couple different things you could do are using custom code to make pagee have seamless transitions when using pagination rather than jumping to the top whenever you click next button. You can read more about that on here:
Or use Finsweet libraries to avoid using pagination completely but that would require you to change your layout in order to utilize those functions as intented, so I am not sure if that is something you would like.
Webflow Experts at Flow Ninja Support Team!