It’s because one of your peripherals is set to wake state. You can google how to figure that out.

Sometimes that’s a firmware issue. ASUS screwed up the ACPI DSDT for my 2021 G15 by leaving the sleep capabilities off of one of the NVMe slots - every time you’d tell the machine to sleep it would try, but because one of the NVMe slots wasn’t capable the machine would then immediately rewake. I had to decompile the damned thing, patch it and load my patched table as an in memory override every single boot.