GML Speeding up cutscenes/gameplay event coding

Hey guys. I'm making a game that is based on missions, during which I have to control things such as enemy behaviours, dialogues, cutscenes, ecc.
Hello :)

I am making a game that has alot of missions and cutscenes.
The way I code them right now is by having the main mission script with a "missionstage" variable, and I play with that to start and end events. I just then "inject" actions into the actors, so that they move during cutscenes and all that.

Now, this method works, but it takes AGES to make missions, and if I don't speed this up considerably it's going to take years to only to code the missions. This isn't ideal.

The problem is that even basic actions need a lot of code and testing.
For instance, let's talk about a small cutscene I worked on. It required the player to get to a point, the camera would then move to a certain point, a character would spawn with certain settings that made him cutscene-friendly, move to a point, do some actions and the cutscene would be finished.

This took me like 3 hours to do. That's way too much.

The first issue I have is that I have to "hardcode" everything. Every time I spawn a guy, I need to code his settings. If a player needs to get in a car during a cutscene I have to do all sorts of funky **** under the hood to actually have the cutscene play, and this is for all things missions, cameras, ecc.

The actual gameplay parts don't take much long at all, it's just these kinds of sequences that take ages.

So I have been thinking of making some scripts that I can reuse for these actions, so that I wouldn't have to code so much every time but oftentimes I find myself in different, unique situations, so I'm here looking for ideas, something like a mission scripting language that I could build.