Twitter Elevated Access?

Ok, Twitter Dev support got back to me; they said this: *The v1.1 endpoints mostly use OAuth1.0a - specifically for the /1.1/account/update_profile.json endpoint you must use OAuth1.0a with user context (from the 3-legged OAuth flow). *
OAuth2 is not available for the old v1.1 endpoints.

I’ve been struggling to make this work. I tried in Postman to use https://api.twitter.com/oauth/request_token. It worked there, which was awesome, so it looks like my credentials were accepted and my Elevated Access was correct.

And I know I need to create this kind of string for the Auth

But as I understand it, the oauth_nonce; oauth_signature and oauth_timestamp are created dynamically for each request. I tried this plugin, but got the below error, which looks the same as previous errors re Elevated Access.

But Postman worked with my credentials, and returned a good 200 response. So is Bubble/the Handler plugin the problem (@redvivi)? @emmanuel any ideas? Any help would be greatly appreciated! @Jici I’ve seen you’ve offered great help before on APIs; any ideas here?