Isn't SS2 on the paid mod store or whatever it's called? It's practically a free DLC/main quest expansion, you're doing yourself a disservice not playing it. Settlements in the base game serve no purpose, there is no reward for building them up nor is there a punishment for failing to meet their upkeep or even failing to stop an invasion. It is a prototype that shipped as a bare minimum lego set for curious players and autistic minecraft fans, doing a settlement/mayor run without SS2 or another mod that completely overhauls the mechanics and rewards you for engaging with the mechanic is a waste of time. How do I know? Because I also made several runs where I did just that, except I had to find some way to give myself incentive at some point and that led to me massively modding the game to give mayor character unique benefits. At least with Raider outposts you get a whole lot of regenerating loot, some of the best stores in the game and unique buildings, like chem vending machines. Even that is a step in the right direction compared to the vanilla game mechanic.
At least watch the series yourself to see what you're missing out on. I already modded settlements myself a long time ago so I don't want to try SS2 in fear of it breaking something for me, but if I haven't this would be one of the first priorities for any character that wants to engage with the system in any way: