How to swap sim card and all data between iPhone 6 plus and iPhone XR

Hello - Could you please advise on the best way to swap the sim cards and all data between my iPhone 6 plus and my iPhone XR? I understand many apps are not backed up on the iCloud, so i can't restore each from backup. Normally I use each phone in separate countries where I live and work, but because of the pandemic I'm now stuck in one place, so I would like to have the newer phone (iPhone XR) available as my main phone. Many thanks.