I save a lot of Instagram reels to Muse. Since every video is stored in full in the Muse Library, it grows quickly (mine is at [X GB] already).
Muse already has most of the pieces: with Full-Size Pictures on, originals live in my iCloud, and the iPhone app only fetches an original when I open it, keeps ~500 MB and clears the least recently opened first. I'd love the same on the Mac – like "Optimize Mac Storage" in Apple Photos:
- Thumbnails, poster frames, metadata, tags, notes and the search index stay local, so boards and search look and work the same
- Originals not opened for a while (or above a storage budget I set) are removed locally and fetched from iCloud when I open them
- Optionally limit it to videos or to specific collections, with "Keep downloaded" for collections I need offline
- A small cloud badge on offloaded items, plus how much space is used and freed
Local-first stays the default and only my own iCloud is used, so it fits how Muse already works. Moving the library to an external drive helps, but isn't practical on a laptop.