Ah if anything its the volume that's different. On SteamOS there are 2 speaker devices in the audio settings and one isn't affected by the volume buttons and acts as a sort of multiplier for the speaker volume. For whatever reason on SteamOS this slider was set to 30% for me. At some point when I learned of this I turned it up somewhat, maybe to 60%, then I just kind of lived with that for several months. On Bazzite this same slider exists but it's at 100%.
Thank you! Someone else replied to my help post saying the same thing. I’ve got an OLED as my main display with a secondary LCD and HDR is on. I’ll try that out this morning when I boot my machine up
I don't recommend gamemode except for very old hardware. It sets your CPU governor to performance which can actually reduce performance on modern CPUs in single threaded workloads (games)