This kinda weird conspiracy theorist attack on Shakespeare has been going on since the mid-19th c or before. Not a peep or suspicion out of ANYONE prior to that, and every extant source sez he wrote his own plays (he collaborated with more than one well-known and prolific, younger playwrite near the end of his career; of “Cardenio”, only one scene and the musical scoring survives), and no one is known to have made any claims against him prior to that time. Whatever it may have become in the current times, this conspiracy theory began as an puff of elistist snobbery, but penned by someone who was not the least part of the elite.
They are not helped by the fact that de Vere was not a talented writer. None of the known writings of De Vere suggest he could have written Shakespeare’s plays or poetry.