Be aware that if you install WDS on the 😄 drive, then want to move it to another drive, the smspxe.dll file will remain registered on the 😄 drive. RemoteInstall will not have a folder called SMSBoot.
I had a server where Config Mgr had been deployed to the 😄 drive but was supposed to be on E:. The roles were removed and "NO_SMS_ON_DRIVE.SMS" was put onto the 😄 drive then Config Mgr was redeployed.
There did not seem to be a way to get WDS to install and put SMSBoot into the RemoteInstall folder.
Digging around in the registry I found entries for it on the 😄 drive and edited them to point to the E: drive (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WDSServer\Providers\WDSPXE\Providers\SMSPXE).
This resolved the issue. I suspect it will help those who are looking for a solution for an empty SMSBoot folder, too.
