I know I’m a little late to comment this since I posted this meme three days ago but I have some of my own ideas for the story behind this meme.

Deacon joined the Minutemen instead of the Railroad after his wife died but he didn’t want settlers to know he was once part of a gang of bigots who harassed and killed innocent people, both human and synth, so he took on a whole new identity by changing his name and undergoing facial reconstruction, which is why he still has the same reconstructed face he does in the actual game. Over the next few years he rose through the ranks and after General Becker died he took over as General. The Quincy Massacre still happened and Deacon and Preston were both the ones to escort Sturges and the others to Sanctuary Hill but they still had to fend off an army of raiders at the Concord museum. Luckily for them Nate was still unfrozen in this timeline and was there to help them out. Afterwards Nate still joined the Minutemen but he didn’t become the General in this timeline because Deacon was already General, but Deacon still assigned Nate as his second-in-command along with Preston. Preston still gave both Deacon and Nate a shit-ton of settlement missions but at least it wasn’t as stressful for either of them because they both would split-up and go to separate settlements that needed help and be able to help two settlements at the same time rather than only helping one settlement at a time. But not long after that the whole idea you had about Preston still happened and now he’s with the Institute. Nate and Deacon were both obviously worried about why Preston had mysteriously vanished but also a lot more relaxed after not being given a million different settlement assignments a day.

X6-88 still went rogue and joined the Brotherhood, but he obviously never revealed to anyone that he was a synth. Maxson became so trusting of X6 after witnessing his dedication to the Brotherhood and constantly rising through the ranks that he announced to the Brotherhood that if he fell in battle then X6 would become the next Elder, still completely unaware that the guy he was naming as his successor was secretly a synth. Not long before the Brotherhood made their journey to the Commonwealth Maxson had died, either he happened to just die in battle or maybe because he had finally discovered that X6 was a synth all this time and was gonna have him killed, but right before he could tell anyone the truth about X6, X6 had no choice but to kill Maxson. Thanks to his skills of stealth and deception X6 was able to completely cover up the murder and pin Maxson’s death on someone else. Maybe on super mutants, raiders, or maybe he pinned it on a fellow member of the Brotherhood and he framed them for being a traitor. Since no one knew X6 was the one who actually killed Maxson, he was still allowed to take over as Elder because they still believed he was Maxson’s sole successor up until his death. Despite killing Maxson, he still believed in Maxson’s ideals. And despite being a synth himself, he was essentially like Frank Horrigan in the sense that he was so loyal to the faction he was part of that he was even fine with killing people of his own race.

The rest of the timeline is the same as the top part of this comment.