Power Automate custom connector: protect pdf-file content with password -- 2

We need to create password-protected pdfs to be able to send sensitive information to students in flows in power automate.
I am looking for a custom power automate with 2 inputs and one output

Inputs:
1. pdf-file-content (for example created by the Word connector:
https://docs.microsoft.com/en-us/connectors/wordonlinebusiness/#convert-word-document-to-pdf or from html-to-pdf)
2. password as string

Output: pdf-file-content secured with password

I believe that what's needed is a logic app that can be called from Power Automate. I am open for other solutions, too.
However, for privacy reasons it would be unpractical to use existing API that will send the pdf file content to an external service.