How to convert my iCloud Photo Library into H256/HEIC/HEVC

I have iPhone 11 Pro and MacBook Pro 16", both are powerful enough to handle HEIC/HEVC. I just found that significant part of my iCloud Photo Library has an unoptimized MOV files recorded on previous iPhones:

Is there any way to convert library to modern format keeping all the metadata?

For images, you could use this iOS app to batch converting anything to HEIF:

I personally use this app for my own Photo Library!

Half - Cut Media Storage in ½ https://apps.apple.com/app/half-cut-media-storage-in/id1288721004

For videos, I haven't test anything solid yet. However, I found a blog post https://rienkjanschurer.nl/how-to-make-your-apple-photos-library-smaller-use-h265-hevc-for-your-videos/

and it uses Permute, which looks promising! https://software.charliemonroe.net/permute/