My Great Wall GW3300 512GB slows down drastically when it's over 80% full in Once Human, how do I fix this?

Loading maps in this game felt like I was running it off a cheap USB stick, and with only 512GB, the drive was basically maxed out after a few AAA installs. Once the free space dropped below 20%, the garbage collection went haywire, and random reads plummeted from 40 MB/s to a miserable 15-20 MB/s, pushing load times over a minute. I tried deleting a few random small files, but it only freed up 2GB and did absolutely nothing for the speed—a total waste of time that left me feeling defeated. I eventually manually triggered a system-level TRIM command and used a partition tool to ensure 4K alignment, while wiping the temp cache. AIDA64 showed random reads bouncing back to 35-42 MB/s, and load times dropped by about 30%. The drive froze for a second during the TRIM process, but a reboot sorted it out. Temps are now 40-48℃. I took a system snapshot of the new partition layout, and the input response finally feels snappy again.