Write amplification issues with NVMe drives – a shared secret
blog.min.io
blog.min.io
I think it is common knowledge that flash drives perform badly when full - I'm a bit surprised that the author ("[...] despite spending decades as a chief technology officer") was surprised by this.
That's also why it's important that discard/fstrim is supported in the entire stack filesystem, operating system, hypervisor, storage controllers, storage device. I managed to fry a flash disk in a Linux software RAID because I neglected configuring md to pass discard commands to the underlying storage.