Validate rest-api call on create

WordPress Site A has an API, which is being used by another system/application (B). B is struggling to handle/controle/sanitize the posts being sent to the API, and often cause creation of duplicates. B is really struggling to solve this in their end, so I was wondering if I can add a validation-method to the endpoint in my end.

Can’t use /wp-json/wp/v2/plugins API endpoint even as administrator

Using Basic Authentication as an Administrator, I am getting an error code 401 Unauthorized : [rest_cannot_view_plugins] Sorry, you are not allowed to manage plugins for this site. error when I attempt to access the GET /wp-json/wp/v2/plugins endpoint of my server. I can pull Post and Page info with no problem, but when I query against the plugins, I’m getting the 401 error. I’ve confirmed that the userid used in the API call should be able to manage plugins using the CLI tool:

call funcution when clicking submit

I’ve built a WordPress plugin, this plugin has a form in front-end using a shortcode
I need the submit button to do two things, first to send the entries to the database which I did it successfully. The second thing is to build a URL from entries and run it