one approach might be to use multiple icloud accounts to shard the photos data by what you want to sync locally vs not (for example by set of years, i.e., mynam

one approach might be to use multiple icloud accounts to shard the photos data by what you want to sync locally vs not (for example by set of years, i.e., myname1980to1990, myname1991to2000, etc). it's an added pain no doubt.