Uknown airport

Why can’t I plan VFR, VFR/IFR, and IFR/VFR flight plans from unknown destinations? In real planning, we can plan flights from anywhere. We simply write ‘ZZZZ’ in field 13 or 16 of the flight plan and use field 18 with DEP/ or DEST/ and the coordinates. There are too many unknown airports, and in MSFS2024 career mode, this limitation is unhelpful."