There’s however a simple workaround to help you share a file or folder in Google Drive with multiple users in one go in parallel using the UrlFetchApp service.
On Pulse Phil recently shared a snippet for changing a Google Drive file permissions from Editor to Viewer. In this example for Amit Agarwal you can see how you can make these types of changes for multiple users without slowing down your script execution time.
Source: How to Share Files in Google Drive with Multiple Users – Digital Inspiration
Member of Google Developers Experts Program for Google Workspace (Google Apps Script) and interested in supporting Google Workspace Devs.