js, css advanced fix for website- especially for mobiles and iOS

(1) carousel with js (owl js) appears in wrong scale at slow-speed loading >> to be fixed so that the layout is already "close to" propoer condition at the very beginning (maybe need css to sort out)
(2) due to use of a couple of JS, the page scroll becomes blocked for a moment while loading. request for a good fix/ instruction on this

-above codes are made on shopify+pagefly
-request for fast work, high urgency