I have been running the public betas on my personal laptop (16" MacBook Pro M1 Pro), my iPhone 13 Pro Max, and my 2015 iPad Pro (12.9"). The betas have been largely solid. After installing the betas I used Photos abiltity to merge duplicates to clean up far more duplicates from my library than I ever thought existed. One thing that has been a bit perplexing is the number of duplicates found on both my iPhone and iPad were substantially higher than on my MacBook. Presumably they are all syncing to iCloud (can find anything I am looking for on all devices). The only device that has full-resolution images is my MacBook (although my Photos library is housed on an external drive). Perhaps this is just a beta thing. Hard to know. Regardless I am hesitant to delete "duplicates from my mobile devices when my Photos on my MacBook says no more duplicates exist. Thoughts?
I wouldn’t do something like that from a Beta-Version.
Unless I become absolutely certain of the cause I have no intention of doing an photo merging on my mobile devices. Just a question of curiosity for me.
I would check this new function, but it looks like its not available on the iPhone X. 