I am not a teacher.
Everyone is singular. The definitive proof is the verb which will always be 3rd person singular.
This is what everyone wants. Everyone knows… Everyone is going to… and so on.
The other issue is one of gender neutrality. Everyone will burn for his sins = Each one will burn for his sins. 'His sins' used to be correct (and hasn't become incorrect yet) but is not acceptable by everyone as it uses the masculine pronoun rather than a gender neutral one. Since there is no singular gender neutral pronoun in English, the plural they/their/them are used. This usage has been in the language for many centuries, but it is only recently that it has become a touchy subject for some people. So, the use of a plural or singular pronoun has nothing to do with the word 'everyone', and everything to do with political correctness.
Student or Learner