Do new iPhones compress data differently when transferring it over from one iPhone to the next?

I had an 11 Pro Max and just recently transferred my data over to my new 13 Pro Max using the feature where you put the phones next to eachother.

Everything looks to be on my new phone, text messages, photos, emails, etc. however my new phone has 18 GB “missing” of storage despite everything looking like it’s been transferred over. I don’t want to reset and trade in my old phone quite yet until I find this out.

I have made sure that all my data is downloaded and not just floating on the cloud so to speak so I know that can be crossed off when it comes to the freed up storage space. So my question is do newer iPhones compress data differently in that it doesn’t require as much space? Or are there any other explanations?