I don't think that's how it works, but yes if a particular manager had brought the game into disrepute (LOL) or similar they could be charged. I don't know the Man City charges in detail but I've never heard of any of their managers being individually responsible for any of the alleged financial misdemeanours. As you alluded to though they would not bring any charges while the PL "investigations" continue, otherwise it could be seen to compromise the due process. As I've already said several times I am pretty sure that the FA are only really interested in the alleged "bullying", because it brings into disrepute their "inclusivity" goals. They may include other charges but thats the thing they "care" about, being seen to be a fully inclusive (woke) organisation.