Teams is backed by Microsoft 365 Groups which technically only support two user types: owners or members. This means that anyone added to a team in Teams is added as a member by default in the backend Microsoft 365 Group. This group also provides access to the associated SharePoint site.
To be honest, although one can manage the SharePoint permissions outside of Teams - directly in SharePoint - it will probably cause more headaches in the long term. It is possible though.
@pvanberlo Thank you. It would make it easier if you could pick within an O365 Group/Teams to add them as Visitors vs Members, which would help in the associated SharePoint site. Seems like if there are connected, they should somewhat act the same.