SQL server Installation I have received a new server. The server has the following specification.
It has 500 gig 7.2K RPM disk,
 SSD
 NVME
1.2 TB  10K RPM disk.

All are in RAID 1.

I am planning to install Windows Sever on the 7.2K RPM disks. I want to install SQL Server on the OS drive( i.e. 7.2K RPM drive). I am planning to keep log and data files on SSD and NVME. The 10k RPM drive will be used for backups.
NVME drive is faster than SSD. 
My Windows team recommend that I should install Windows Server on the SSD or 10K drives for performance. But all I care is about SQL Server performance. I don't think that Windows Server will perform badly on the 7.2k drive.

Does anyone see a reason to install Windows Server on any drive other than the 7.2K RPM drives?
In short, put the OSes on slow storage and all the data/log &amp; backup files on fast storage.

I know that my environment is different that yours, but I think similar principles apply.  We have a SAN and the storage pools range in different speeds, 7.2k, 10k, 15k.

We install the OSes on the slower drive pools and have all backup files and data/log files stored on the 15k drives.  There was a time when we accidentally put everything on the 15k drives and we didn't notice a performance difference.  It was brought to our attention by our SAN admin after an audit that the OS was stored on the faster drives.

We monitor SQL Server performance with perfmon and Dell Spotlight.  For grins, we went and looked at the historical metrics that mattered, and saw nothing to note.