And you also have to consider keeping about 10-15% of the drive space free for operational functions. Unlike a HDD, you can't defragment the drive to magically free up space when you think it's needed (you should actually NEVER defrag an SSD).
main reason to keep about that free is speed. Once you get below 10% free space on an ssd it will slow down to almost hdd speed in some cases.
I would avoid dramless ones as the main reason to get an ssd is its faster, and dram helps the write rate by concealing the slower memory modules from pc and making it think its faster. Some nvme have a variable cache to write to depending on how much free space you have and drive size
just some website
The 970 EVO Plus's write performance varies based on how much data lands in the TurboWrite cache, which is a small section of faster SLC-programmed flash that's used to boost performance. Samsung's EVO Plus has both a default TurboWrite cache capacity, which doesn't change regardless of conditions, and an Intelligent TurboWrite region that varies in size depending on the model and the amount of free space on the drive.
For instance, the 1TB model provides 6GB of TurboWrite capacity. Beyond that, Intelligent TurboWrite steps in and scales up to an additional 36GB if you have enough free space on the drive.
I have a samsung and used its software to allocate an additional 10% of drive space to error correction etc. I had only planned on a 500gb nvme but got a 1tb model for same price, so I have too much space. I already had a 3tb hdd. I don't use space, having lost a few hdd in a row 14 years ago and being bitten enough. so 3.7tb of space with only 200gb used
not here to convince anyone to change anything, just commenting
as for defragging ssd, while you shouldn't or don't need to, windows does defrag 1 part of the ssd once a month, but only on C drive. So it won't affect this case - https://www.hanselman.com/blog/the-real-and-complete-story-does-windows-defragment-your-ssd
and windows defrag isn't the same process it used to be, its actually disk management and knows what to do with an ssd, it runs trim