Solution
_ = (
User.query
.filter(User.roles.any(Role.name == default_role_name)) # 1
.filter(~User.roles.any(Role.name != default_role_name)) # 2
.delete(synchronize_session=False) # 3
)
_ = (
User.query
.filter(User.roles.any(Role.name == default_role_name)) # 1
.filter(~User.roles.any(Role.name != default_role_name)) # 2
.delete(synchronize_session=False) # 3
)