The UPS compartment definitely sounds like something nobody would ever manufacture power armour without, so yes, that sounds like the best solution.
Speaking of power armour…
Is it possible to wear anything as well as the armour or helmet?
I mean, if you were using a hauling frame, can you use the volume to wear armour under your power armour?
Or if you’re wearing the helmet, can you use light amp goggles on top of it, or not?
If not, what about adding crafting recipes for adding functions to the helmet? You’d think advanced powered armour would come with functions like that anyway.
Maybe scavenging bits from the eye CBMs and installing them into the helmet eyepieces? Installing a rebreather into the helmet?
There are quite a lot of devices in game that it could be useful to do that with.