Is it forbidden to publish beneficial videos on YouTube, free from impermissible content, if the platform might display impermissible advertisements without the channel owner's permission?

There is no harm in uploading beneficial clips to YouTube; rather, it is encouraged due to its role in guiding to good and earning reward, as the Prophet, peace and blessings be upon him, said: "Whoever calls to guidance will have a reward like the rewards of those who follow him..." The presence of impermissible advertisements, over which you have no control, does not prevent the dissemination of good. The sin of viewing them falls upon the one who commits the act, not upon you.