Ngl, I didn't think about how the in-universe Dispatch game would work, but I imagined it to be very close to irl Dispatch, just with a few things tweaked for Privacy Reasons on SDN's part. But here's some concepts I'm gonna throw out there:
SDN created the game to 1, promote their subscriptions, and 2, to promote good publicity for the Phoenix Program(this is with he assumption that the game features the Z-Team or at least the new made-up heroes that are a part of the Phoenix Program in the game universe of this AU's Dispatch)
They made the game centered around the Phoenix Program because the redemption story is too good of a plot opportunity to not capitalize on.
If the characters are fully fictional, they'd still be based off of pre-existing heroes and they'd either ask those heroes to voice them or hire popular voice actors. I think at least a few members of the Z-Team would end up with a character inspired by them and would voice them(I can especially see this for Prism)
If the in-game team is actually the Z-Team, they based some calls and scenes from real calls the Z-Team have handled before and took the voice lines from the recorded comm files(since comms are canonically recording) to put in the game. However, some things needed to be tweaked for Privacy or to make it HR/PR-approved or to make it seem more professional while still being comedic enough to be entertaining. This is when they would bring the Z-Team in to record lines for the game(and also for any added dialogue lines and scenes for variety).
There is 100% a ManMech cameo somewhere in there, maybe as one of the callers/subscribers or as one of the background SDN workers(he could even become this Dispatch's Galen if Galen decides to not be a part of the game).
Robert was obviously aware of the game's production because it is centered around the Pheonix Program and was questioned by SDN for advice on how to represent the redemption plot and the characters(Z-Team or made-up). However, what Robert didn't know was how accurate the actual Dispatching would end up being. It's literally a one-to-one comparison to his actual job. The only difference is the hacking, which is greatly simplified.
The Dispatcher character obviously can't be Robert for identity reasons because I think SDN would still have the Dispatcher have a similar backstory to Robert in terms of how he ended up as a Dispatcher(aka retired hero who strikes a deal with SDN to get help to get back in their feet to be a hero again. Of course, they change how they were hired because Blazer's interview was... questionable.) for that juicy Side Plot. I think instead, the character would be someone more gender neutral to represent the Player character and have a more vague character to allow the decisions of the player to mold who the Player character is(in contrast to Robert in irl Dispatch, whose character and personality is very established and distinct and the player mostly only getting to choose how he says something and who to romance in the dialogue scenes). They still have a pre-determined name for voiceline reasons but the player still gets to decide the kind of person the Player character ends up becoming in the game.
The romance would obviously not be a part of the game, especially if the Z-Team are being used as the main team, because the spotlight is meant to be on the Z-Team as a whole, not specific people.
If Shroud remains the main villain, they'd have a voice actor do an impression of Shroud, and when he appears in the game, ManMech just freezes because holy shit, why is the impression so good??? It's like- scarily accurate. But what Shroud is after would have to be different to the Astral Pulse, again, for plot reasons.
SDN would have to be very careful about the changes they make, especially to the Player character, to make sure people can't say "That's really similar to what happened to Mecha Man actually... Wait, is the irl Z-Team's dispatcher Mecha Man???"
Overall, a lot of the animated scenes would be completely different. Idk what they'd be like though.
There is still banter over comms in the game, but it's toned down to be more appropriate and HR/PR-friendly but still including enough for the player to connect with the Z-Team as genuine people.
The Player character has a different life outside of work than Robert because obviously, SDN wouldn't know that much of Robert's personal life and even if they did, they wouldn't showcase it. The Player character is established to have a cozy-enough but cheap apartment for them to seem more grounded and practical as a person, but is a crazy workaholic who is also isolated and feels as if their life is empty and dull without being a superhero, like being a hero was the only interesting thing about their life. They still did things outside of work(unlike Robert) but it all felt too dull. In comes the Z-Team to shake up their life and show them how to have fun and to give them that companionship that they were missing out on, similar to Robert in the game.
When the Z-Team were recording lines for scenes with the Player character, they just imagined they were talking to Robert, so in the game, they end up treating the Player character similar to how they treat Robert.
I think the Player character would have a different personality to Robert and also processes things different. Maybe SDN would showcase more of the negative consequences of being a hero, like the Player character has nightmares about old fights or they look at their scars with judgement and insecurity, unlike Robert in irl Dispatch, who is so jaded about it all and has either repressed it or just accepted it. I think the Player character would have a harder time getting over some of the darker parts of their experience as a hero.
Now I feel like writing a fic of ManMech playing this game and experiencing the altered plot... but I definitely don't have the brainpower to plan it out right now and commit to it.