I did all 4 faction endings on vanilla FO4.

I have a Merc type PC (Willy Jackson) I have been playing with in a heavily modded game. And man I have had fun playing as him in FO4. He did no settlements, after getting paid for helping Garvey and his crew he headed for Boston. Any paying jobs along the way he took. Once he found Diamond City he liked it and bought the Home Plate house. That is where he has lived the whole game.

I have come to a cross roads where the game story will want me to choose a side. He was interested in the Institute and the possibility of his son being there (albeit skeptical) but was disappointed to find his son's ideology had been heavily influenced from growing up underground in the Institute. I wish there was a choice where the winning faction was randomly decided by you doing nothing. Because after losing his wife and waking up in a [censored] up world Willy is on Willy's side.

You could just ~not~ finish the main story. I played through all endings once, but on my current game (reloaded from before the final choices) I just haven't ticked off any faction yet. One would think the railroad might wonder what's taking me so long in the Institute and the Institute might wonder what's taking me so long to relay over to the Mass Fusion building... the Brotherhood might be wondering what's taking me so long to finish patching up Liberty Prime... but they can all stay in that perpetual state of waiting for me.