Kong requst transform -jwt.sub.token. How to inject the jwt sub?

[Jensileus]

I run a kong gateway as a first entrypoint with openid for veverifying tokens. I have a oauth2 auth. server running on my ubuntu server. I have a webapp running react where user can post, and other things. So kong is the first entrypoint and i have different microservices both rest and graphql server running after that. For my microservices i dont want to decrypt the token and get the sub everytime i need a user spesific task done, so i want to inject the sub upstream from my kong gateway. I have tried this with request transform, but i cant get it to work. Like i said i have openid that cehcks the token, and this one works - i have tried. So now i want to inject the sub from the token and send that with the request. so i´ve tried some diferent headers like: X-User-Sub: {{jwt_claim_sub}} and a lot of others, but it want work. Please help.