If your Mac doesn’t have enough space, export them to a USB hard drive or if you’re using the download originals option, first move your library location to the USB drive as also described on the link above.
That's exactly what I expected to work, but for some reason this approach failed for me on a new Mac with an empty Photos library. I enabled "Download Originals," but 10+ years of iCloud photos never appeared. There's no manual "fetch all from iCloud" button, no progress indicator, no way to diagnose what's wrong - the sync just silently fails. Luckily, iCloud Photos Downloader bypasses Photos entirely and pulls directly from iCloud.
You were absolutely right. Someone in the thread mentioned a status indicator, and it triggered me that I hadn't seen it at all.
It appears that on Monterey I need to pull the page down twice to show the sync status, and when I found it, the message said that photos weren't syncing due to "Performance."
Here’s the official documentation page for exporting directly using Photos for Mac without syncing everything locally: https://support.apple.com/guide/photos/download-photos-to-yo...
You can also choose to sync all photos locally with Photos for Mac by setting “Download Originals to this Mac” as described on this page which is what I do to keep a local copy: https://support.apple.com/guide/photos/photos-settings-pht51...
If your Mac doesn’t have enough space, export them to a USB hard drive or if you’re using the download originals option, first move your library location to the USB drive as also described on the link above.