You will want to use the following call - Swagger UI
Which let you assign view, edit, delete permissions to specified entity for specified user or user group.
To avoid issues/confusion, please read my explanation below.
Each user has it’s own unique GroupId (user specific user group) in the above call you can use that or GroupId of an actual user Group.
Each display has it’s own unique displayGroupId (display specific displayGroup) you can use either that or displayGroupId of an actual displayGroup
Entity - in this example it will be displayGroup
ObjectId - in this call displays operate on displayGroupId (not the displayId), which means you’ll want to call GET display first to know what displayGroupId to use.
groupIds - it can be either user group groupId (visible in web ui as well) or user specific groupId - you can use GET /user call to find the user specific groupId if needed.
The call itself will be as follows:
POST /user/permissions/{entity}/{objectId}
entity:displayGroup
objectId:6 (displayGroupId, display specific or actual displayGroup)
groupIds[11][view]:1
where 11 is the GroupId (user specific or actual userGroup), 1|0 flag to grant permissions to [view] [edit] [delete] actions.