While the addition of the GPU as one of the ground services equipment is a nice addition to update 22.4, it serves no real purpose in the pre- or post-flight because it doesn’t provide AC electrical power to the aircraft systems like it’s supposed to (similar to when the APU is running).
For example, aircraft lights and instruments should be turned on when external ground power is connected so we wouldn’t have to turn on the APU. In reality, this saves fuel because the APU does burn fuel which is also not accurately portrayed in IF yet. Just a small attention to detail.
Keep up the good work!