Usenet was the solution: ads were not accepted there precisely not to turn it into the crap that web has become much later, but some big names decided to destroy it, and as of 2023 they mostly succeeded. The protocol is free, although it would likely need a significant overhaul to make it more robust, secure and censorship proof, possibly by introducing delivery through distributed encrypted p2p.

BBS, Gopher, Usenet, and friends are all still there - no need to invent a new protocol.