N-of-N multisig is too much disagreement when N is big, like one thousand, one million or more, one person rejecting to sign can destroy the whole concept. If you want to use CPU for mining Bitcoin, it is better to find some cloud miner, lock some funds in 2-of-2 multisig Lightning Network channel and then you and the cloud mining service both put the same amount of coins in such address. It can be one-direction channel where you can receive some rewards for your shares in single satoshis. If there will be many users, it may be profitable, but expect rather 1/1000 th of satoshi payments (or even less if needed, since when going off-chain we can split the coin to even smaller parts as needed in the future).