You have to change the setting:
It must not be me (the team leader) who has to go looking for my team members, but it must be the other players who are looking for the team they like (on a page that includes a list of all the teams created by others) and offer themselves to be a part of one of them.
The current method of forming a team (with active research to be carried out by the team leader) does not work, it is wrong, it is not able to match "supply" and "demand"...
... in fact, in the current setting, whoever supplies his offer (the team leader), does not have the possibility of exposing it to the potential interested public, but must already know who the 3 users interested in his offer are, and call them to himself.
it is as if a florist could not open a small shop in his own city (and advertise on TV, in newspapers, billboards, etc.), but the only way to get in touch with his potential clientele was to call the citizens one by one to ask them by telephone if they were interested in buying a bouquet of flowers... it is clear to everyone that this method does not work.