My first impression about the new case (BIQU Aluminium case) is fantastic. It dropped at least 20° Celsius while idling or watching preview videos at around 52° even with moderate overclocking (arm_freq=1300 core_freq=500 sdram_freq=500 over_voltage=2). Before this case, it was sitting around 70° without any overclocking. Now, I don't know how to test properly, but I am happy if it stays stable and cool and if I don't get any over heating warning symbol while playing 8- and 16-bit console games with shaders.
Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first