Is there any way to add a new relation to a one-to-many

System Information
  • Strapi Version: v4.0.7
  • Operating System: Windows 10
  • Database: mysql lite, the default with strapi
  • Node Version: v16.14.0
  • NPM Version: 8.3.1
  • Yarn Version: it is not installed

I created a relation field in the default user that was created by strapi, basically, a user can have many “dado” which is a content type, that content-type can have only one user, i created a custom endpoint to insert data in that “dado”, i can relate that dado with the user easily, but when i try to get that “dado” with find one it returns everything but the id of the user that it was associated, i can see it when i go to content manager and look at the “dado”, and another thing, after creating that “dado” i want to add that relation to the user, but i can’t find any way to do that, if i try strapi.entityService.update it removes any other relations that the user had before of that moment.