Change certain settings among Us afterwards?

In Among Us there are some game settings that you can't change in the lobby itself. This can only be changed before the lobby is created.
(For example the number of impostors or which map is played)

In any case, I've often joined a lobby in which the Impostor or Map settings have changed afterwards.
For example, I played several rounds in the same lobby and suddenly there were 2 impostors (it was the same lobby). The same thing happened with the map, suddenly it wasn't The Skeld, but Mira HQ.

In addition, there are very often people who literally spit on the host to change the number of impostors or the map.

But you can't change these settings on the laptop in the lobby.

So now my question:
Changing it afterwards is a hack
or if not, how do you change the settings afterwards?

Where you can choose your hat are these boxes at the top

this is english but you have to press on the far right where it says game

Thank you, but I don't have these fields. For me it starts with Confirm Ejects.