That explains why my 2017 Dell XPS 13 9360 with an 8th gen i7 never went to sleep properly. Originally it would just keep running the fans and the battery would drain. Then after a while it seemed to start sleeping but never turned on again so you’d have to reboot anyway. In the end I wiped Windows 11 off it and installed OpenSUSE Tumbleweed. Now shutting the lid works just fine.
I also have an XPS 13 9310 with an 11th gen i7 and Windows 11, and if I close the lid it seems to sleep but sometimes I come back to a completely dead battery.
I don’t really understand the point of Modern Standby. Who wants the laptop to do things when it’s closed and possibly in a backpack with no ventilation? That’s when we want it not to do things.