Hi @Abdulazeez Asaju ,
The Safe Mode behavior suggests that something loading during a normal startup may be hiding or removing these files. I cannot confirm the cause from the available information, but this does not look like a normal IIS configuration problem.
A similar case was eventually traced to malware using a driver to hide files. This does not confirm that your server has the same problem, but the symptoms are close enough that I would check for it before rebuilding the server again.
Disclaimer: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classifies as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
I would temporarily disconnect the server from public access and run these commands from an elevated PowerShell window:
Get-WebGlobalModule | Select-Object Name, Image
driverquery /v
Check for any IIS module or driver that you do not recognize, but do not remove anything until it has been identified. I would also run Microsoft Defender Offline and check whether the sites' web.config files contain a hardcoded <machineKey> copied from public documentation or another server.
If an unfamiliar module, driver, or reused public machine key is found, the server may be compromised. Restoring only the IIS files or reinstalling Windows and restoring the same site configuration, may allow the problem to return. In that situation, your security administrator or Microsoft Support would need to investigate the server directly.
If you found my response helpful or informative, I would greatly appreciate it if you could follow this guidance. Thank you.