To what extent is it legitimate to present the false accusations made against me by a person who does not fear God to those around him, with the aim of deterring him from oppressing me?

Slandering Muslims, falsely accusing them, and bearing false witness is a major sin. Allah Almighty has linked bearing false witness with associating partners with Him, and He has threatened those who accuse chaste, unaware, believing women with a curse and a great punishment. The Prophet, peace be upon him, warned against belittling a Muslim and clarified the sanctity of his blood, wealth, and honor. If direct advice is not effective, one can seek the help of others to advise him. If that does not work, one can complain to the official authorities or do what you have mentioned.