Ultimate Campaign from Pathfinder 1 is certainly the more involved system. Personally, it's a bit TOO involved for my own particular tastes.
I have not yet run Cult of Cinders, so I can't say from experience, but the more streamlined version of base rules appeals to me.
The "repair this part, or that part" downtime activities in Cult of Cinders may or may not apply to your own home base. But I can certainly see Administer and Organize Labor being core aspects. All of the Upgrade activities.. Build Infirmary, Build Library, Build Training Facility, Upgrade Defenses... those are excellent bread and butter downtime activities that can apply directly, or be easily modified to fit your own context.
The real value to Cult of Cinders' home base rules is that they are all simple skill checks. You're not tracking any sort of build points or anything like that. Hiring labor for the jobs costs money, sure, but as an adventurer you're already tracking those. So it's just time and cash and skill checks. I imagine you could rip through a month's worth of downtime spent focusing on a home base in 10 minutes and have it feel satisfying to the players.