[2023] Game crashing when opening skill menu.

The only way is to restore a backup from before you manipulated the config files and loaded up the save with them. Make sure you have configuration files correctly configured and then start a backup before playing with the prior changes.

You find backups in /steamapps/common/Eco/Eco_Data/Server/Storage/Backups. Check the folders with the name of your savegame, use the one that has the nearest time and date where you didnt yet play with the changes and copy it's content over to the Storage main folder, then load the world.