Is there any wings 2 which has no external certificate requirement ? And t-factor less than 2 ?

Wings 2 has lot of different roles. Not each role will give good hikes. For e.g if you do scrum master they hardly increase 5% in PP1 but if you do AI, Data science then it goes 20% in PP1

I think mostly all roles require external certification. If there are no external certification then value of the role won't be high

You should rather ask your account which role they want you to do. Because they don't give power play 4 role tagging if you ignore them. External certificate will be reimbursed if proper process is followed.