The payloads are listed to low earth orbit, say 300 km height. But space solar power from such orbit is problematic. An individual satellite stays only minutes visible from each ground site. The satellite is shadowed by earth almost as much as ground solar power.

Maybe some medium earth orbit at say 7000 km altitude could work? Outside the radiation belts, but avoiding shadow. Getting payloads to 7000 km requires a lot more delta vee (=fuel) than to 300 km. You probably wouldn't want to use reusable chemical rockets for that part, instead an expendable chemical third stage. Or ion propulsion (maybe even a tug going back and forth), but then the going is slow and you will spend time in the radiation belts.

Starship is definitely big enough to carry up a third stage.

One thing worth noticing about Space Solar: most of the engineering difficulties relate to supplying users inconveniently sat on a planet.

For supplying users already in space most of those issues just go away.

But in-space users already can use solar power of their own. So you're not providing that much competitive advantage.

Not so effectively if they're far out from the sun.