Spawn Wave, a tech and video game YouTuber, dove into this issue on his channel. Though it's possible for the liquid metal to pool in your PS5 if you store it upright, he argues in a video that Sony's design has attempted to reduce the chances of this happening — meaning your vertical console is probably fine.

“Sony did go above and beyond here with this barrier," he said.

It seems that the best way to store your PS5 console is whatever way fits your gaming setup best — but if you start to have issues with the console, consider switching its orientation if you suspect the APU may be the issue.