i've been pondering this idea for a while now - due to highly operational nature of lightning based fund the more appropriate vehicle would be investment grade corporate bonds with the disadvantage that there you NEED to produce returns

another option would also be tokenized security - the way Blockstream did their mining note

nostr:note1tev2mmzf4kmr95ud22js0hj0l2ztgejk9j9mkdufchhuy4vaf27qz33aff