This may be my display, but I just noticed that my display is hardware gamma-inaccurate, to say the least.
I spent some time trying to adjust the gamma on the display but it did not respond at all to any of the gamma-related commands, as in, it did not cause any effect. The confusion over whether this is a ST7365P or a ILI9488 did not help matters as datasheets are quite different when it comes to setting and interpreting the gamma tables.
I tried software gamma correction, and I needed to use a value of 0.3 to get close to what one would expect.