Plesk, Ruby 2.6.3, Rails 6 and website to public folder?

My host uses Plesk Obsidian with support for Ruby 2.6.3 / Phusion Passenger / Rails
so i decided to install Rails 6.
My rails app is deployed with git in httpdocs/myrailsapp.
So far so good.

The thing is though that Plesk sets website at httpdocs/myrailsapp/public with Application Root: httpdocs/myrailsapp

Resulting in the website serving the static index.html of the public folder.
If i delete the index.html then the website hangs… 403 Forbidden / nginx error.

How do i fix this and set the website to my rails app root folder?