There’s a book called Tabletop Role-playing Therapy: A Guide for the Clinician Game Master by Dr Megan A. Connel that’s a really standout resource about this, she appeared on the official D&D podcast a year or so ago talking about it.
I’d say that this is more a resource for therapists to use TTRPGs than it is for DMs to act as therapists for their players. There’s a fine line between accommodating your players’ preferences and needs and providing unwanted therapy; if you want to actually put any therapy techniques into your game, ask your players approval first.
The most common cheat is probably gaining money or experience, but there have always been pretty extensive mod menus for GTA Online with tools from invincibility to making your vehicles rainbow, to randomly causing other players to explode or setting hundreds of muggers on them.
In 2015ish, I used to cheat, other than getting rich, all I was interested in doing was making an indestructible chrome bus with smoke trails that I’d drive around picking up players in, to teleport us all to North Yankton and back like a tour guide.