Are you able to move the wiper arm by hand? If so, at the end of the arm you can flip up a cover that protects where it is bolted on. See if that is loose. If it isn't, remove the nut and wiper arm to see if the arm itself is stripped where it mounts to the assembly.
Let me know what you find or if you have other questions.
Take care and God Bless,
Tuesday, February 9th, 2021 AT 6:50 PM