Hi,
Pls check out:
- Restore Missing Windows Update (wuauserv) Service in Windows 10/11 [Direct download]
- [Fix] Missing BITS Service in Windows 10/11 [Direct download]
After applying the REG files, restart Windows. Also, make sure that the "Update Orchestrator Service" service exists in the Services console. If it's missing, restore the service by running this REG file (Src page).