This month PowerApps has released the preview of the horizontal container and vertical container layout containers that further improve the experience of creating response PowerApps. PowerApps user community has been asking for responsiveness in PowerApps for quite some time and this feature is now available.
Have a look at my blog on the same
https://summitbajracharya.medium.com/responsive-powerapps-with-horizontal-and-vertical-layout-container-497945d9b6b5
