The solar arrays are fixed on one side of the ring so the station will need to be constantly adjusting for optimal solar angle. That is going to take some energy. I question whether those arrays have enough surface area to supply the needed power for all station functions.
A few random things that come to mind:
1. Its worth noting that renderings of aspirational things like space stations--especially when released far in advance of any actual hardware manufacturing--are not necessarily rooted in deep engineering, so its premature to claim foul on the size of an array with just that data point.
2. By far the biggest power draw for space objects is high power communications--look at Starlink or geocomm sats and they all have proportionally large solar arrays vs something like an imaging (optical, SAR, etc) sat. An orbiting space station is not going to have that comms-level disproportionately high power-to-size ratio, nor would one figure it has a particularly demanding thermal environment (if you need to actually create heat on board its all resistive and that can get power hungry, and obviously you'd want to avoid that), so its pretty fair to assume a forward-looking design would have a pretty 'visually small' power system, all things considered.
3. Its worth noting that nobody's ever built a mega space station, so control of such a platform is going to be breaking new ground regardless. One could assume its just scaling of existing concepts (spinning wheels, leveraging earth's magnetic field, etc.), but its such a huge step that there may be other variables at play.
4. An object does not need to fly in an intuitive orientation like, for instance, something in the atmosphere. Most to-date space vehicles point toward earth (for obvious reasons) but a space station doesn't have that limitation. So...that space station can be oriented in an intuitively wonky attitude that, for instance, maximizes sun exposure (either a static orientation or with some dynamic sun tracking).
5. Attitude control/pointing, at least for to-date space vehicles, is largely zero-sum energy if the maneuvers are there-and-back-again. (= spinning into a new orientation B and then spinning back to the original orientation A).
6. At least from a power generation perspective, a mega space station in LEO would benefit greatly from flying sun synchronous near the terminator--that would put it in basically full sunlight all the time, which would significantly reduce the size of the power system (fewer solar cells, fewer batteries) and would also make the thermal environment much more stable and thus much more manageable. (It would also generally minimize drag and maximize gravity gradient too...though the radiation environment is worse).