You should check out the Buildfile method by CrazyColorz and CirclesEverywhere, It helps you insert probably anything via event files, just like chapter events. Every event you want to insert in your rom is included in a big event file (buildfile) and then applied to the rom with a .cmd
So it creates a new rom from the clean rom you’re using. So you don’t need to do any backup of the original rom.
Check this out :
Everything Assembler WIP Guide
And for texts in particular :
Text Processor (for use with buildfile method)