Tower Plus EBT2250, won't sleep

My brand-new Dell Tower Plus EBT2250 (Win 11 Pro) won't sleep. Screen shuts off, power light goes out, but fan keeps running. When my other Dell PCs go to sleep, power light goes dim and bright while sleeping.

Moving mouse wakes PC up okay.

Ran DISM and SFC - no errors

Dell support checked all my power settings ok. now they want me to do an operating system reinstallation, which would kill all my apps and data. sounds like overkill!