Partitioning Advice - Single SSD

I have two 2 TB Samsung T7 external NVMe drives I use to make images of my systems. On my pc's, I only have one SSD, with each one with only a single C partition. On two of them, the SSD has 350 GB of data. Using the external SSDs, I can make full backups of the entire SSD in between 10 and 15 minutes using Macrium X. I have a few older external hard drives, where I back up data only using FreeFile Sync. The few times I had two or more hard drives, I would put data files on one and the OS and apps on the other.

i have a 1TB NVMe M2 type SSD and i partition the drive into two partitions 25% and 75%.
the 25% (C: drive 250GB) is to install Windows
the 75% (D: drive 750GB) is where i move all my folders to and keep my personal files

Documents, Downloads, Pictures, Music, Video are moved to D: drive

Desktop/Program and all Windows file/folders stay on C: drive

this way i can repair/reinstall Windows and my personal folders remain intact
note. i still have external drives for backup.

thats my setup
best of luck Steve ..