Perhaps the better way to get paid is to include a small and well-throttled cryptocurrency miner in the library you are open-sourcing, as a require-to-run part

Perhaps the better way to get paid is to include a small and well-throttled cryptocurrency miner in the library you are open-sourcing, as a require-to-run part of the license. No invoicing, no approvals, it runs, you get paid in fairly direct proportion to the actual run time. This might actually be a real use-case, not that I think about it (of course, then there will be a war to strip it out, violating the license, etc.)