No need to jump to the other category, I can help you with this, the steps can be tedious but it's very simple if you know how to do it:
1. Install skript reflect
2. Import the Minecraft map font class
3. Make a function that takes a list of strings and returns a list of strings, this will be the centering function.
4. In the function loop each string and get the pixel width, remember that between each character is a gap of one pixel.
5. Get the one with the greatest pixel width and by using spaces and the bold tag (this is very important as it can give strings a bit more width), loop the lines again and add `greastest pixel width - loop-string)/2` pixels worth of spaces at the beginning and end of each string (you don't necessarily need to do the end but you can if you want to be safe), and boom, you have it.
Note: the Minecraft map font doesn't account for all characters, foreign ones must be hardcoded, unfortunately.