I didn’t know that Timeshift could work with Ext4... Interesting. Thanks for the hint.

That said, I’m happy with the trade-offs of a CoW filesystem at home. Instantaneous snapshots are a great feature overall. They let me treat my bare-metal deployment almost like a VM. While I did have to customise Snapper a bit to avoid an explosion of snapshots (which can slow down the filesystem), the performance hit isn’t too noticeable; at least on dev laptops with NVMe drives.