Scribble VS iota

Just use Scribble. Your method is highly inefficient using an object for each character, and Scribble will handle everything you need and a lot more very efficiently.

I believe Scribble has solutions for this sort of thing.

You may also look into /u/JujuAdam's Scribble if you plan on doing lots of text rendering.

Use Scribble

I recommand the plugin Scribble by JujuAdams. It’s way, way better for writing text than the vanilla way.

I wrote two specific libraries for this: https://github.com/JujuAdams/chatterbox for branching dialogue and https://github.com/JujuAdams/scribble for text rendering. The former is being used in Schrodinger's Catgirl, the latter is being used in Shovel Knight: Pocket Dungeon, Poinpy, Skies Of Chaos, and a bunch of other commercial games.

If you'd like a practical, working example then you can read the source code for Scribble.

Don't try to re-write GameMaker's built-in systems (with the exception of this)

Yup so there has been quite a few releases since that video. If you want to follow along the version you want is the same as I downloaded 7.0.3 (https://github.com/JujuAdams/Scribble/releases/tag/7.0.3)

The good news is that there's a much easier solution: Run a fixed amount of steps per second, regardless of framerate, aka, Fixed Timestep, for that I recommend using iota, it's on github and open-source. Then you can easily decrease the amount of Steps per second, using the set_time_dilation function, iota also has built-in interpolation functions, so even if the amount of steps decreases to a fraction of 60/s, you'll still get a smooth image.