It seems like this asset would be a really good companion for your cutscene engine: https://the-any-key.itch.io/window-link-game-maker-studio
Cutscene engine for GameMaker Studio 2
A downloadable asset pack for Windows, macOS, and Linux
With cutscene engine you can easily make awesome cutscenes to your games. It works on any kind of game.
There are over 30 functions and more will be added.
There can be options/choices in the dialogue
It's easy to use and there are examples.
Not just a cutscene engine. With this powerful tool, you can do many other things too!
This engine is constantly improved with your feedback and new features will come. Price may increase later.
Also available on GameMaker Marketplace: https://marketplace.yoyogames.com/assets/8241/cutscene-engine
In order to download this asset pack you must purchase it at or above the minimum price of $9.99 USD. You will get access to the following files: