You will need RPG Maker MZ.
Create new project > paste the game folder into the project folder wherever you created. Decrypt all the audio and images files. You can use an online decrypter for that > paste them into your project. This will allow you to see and use audio, images files inside the project. After this make sure you save the project to able to launch the game through the editor.
Now if let's say you want to edit comms dialogue then at the top there will be gear looking icon which opens the data base. Select Common Events on the side bar. Common event 159 has Duston comms mission dialogue, 161 has Harry comms, 163 has dlc comms assuming you have the dlc. I think 162 is for recollection room comms so beware.
If you want to edit recollection room CG scenes then the best thing you can do is find recollection room map in the editor. Right click on the heart icon of the scene you would like to edit and press edit. Right click on the transfer player line and select edit again. This should show in which map the scene happens so now close all the event editor windows and find that map in the map tree.
After finding the map there should be a event editor square place somewhere outside of the map bounds. Double click it and now you can edit dialogue and other stuff to that scene. Keep in mind some maps have multiple event editors placed outside map bounds.
Once you're done with all the editing > save your project > go to your project's folder and copy the data folder and paste it in your original game folder. Obviously do make backups just incase you mess up something. It's also possible to skip this whole process and just play the game through the editor.
Hope this helps.