High discharge 18650s can provide 20-30 amps, doubt the lamp needs that much current if it’s powered off older battery tech

That’s fair

If you wanted to try to make your original rubber band idea work, you could try moving the central dart up slightly so that the rubber band forms a triangle shape and adjust the contact points between the rubber band and the darts to be at each corner of that triangle

If you’re using BTRFS and know how to/are prepared to learn, just create separate sub volumes instead of multiple partitions. Means that you don’t need to decide how to split up space between different partitions and they are easy to delete without a live USB.