If you can find proof of that for 970 evo, 860 evo and for the 850 pro I will stop using it in magician.
Show me!
The proof is that disk works fine and within expected parameters without installing Magician and manually setting OP.
All benchmarks are done without using manual OP.
I think there is some misconception about OP. All modern SSDs are automatically using free space as OP.
OP is NOT some turbo magic cache.
They obfuscate physical internal memory cell layout - provide to OS virtual "CHS" (you need sectors for FAT) and they manage internal cells layout themselves.
To OS writing 1 bit on SLC, MLC, TLC or QLC disk is the same, but we all know it's actually different on cell physical level. This is why i.e. Windows doesn't even have de-fragment option for SSD, just TRIM.
We also know that as SSD becomes more filled it's becoming slower in writing as it needs to reuse/overwrite/reorganize cells that already have some info there.
Conscious user would then leave some free space by himself so the drive can operate properly, have wear leveling and generally "breathe".
Here comes the OP option - it does the thinking for you. If you set 10% OP then 10% of cells will always be "free" since the partition size will be smaller and disk firmware now communicates to OS 10% less capacity. Even if you fill disk to 100% in OS it's physically 90% (as you can fill only 100% of 90% now with user data).
Why would someone use this? Maybe someone doesn't want to think about it and frequently fills the disk but want to have good performance anyway.
Or better use case would be network environment/shares - even if users fills the disk to 100% of available space it still has good performance.
Conscious user that knows about this doesn't need OP.
BTW graphic in Magican is also misleading because it shows last 10% of disk set as OP - this is not true, those cells position will change over time as disk fills and wear leveling takes place.