I found a problem with volume level in Youtube.
When the Picture-in-picture window pops up, the bar usually is at 1/3 to 1/2 of the volume level, but in the youtube window/page is set to max. I can push it in the window to the max, and the volume level goes up... until next song. When push the volume to the max from the PIP window, there is no distortion, just the music sounds better. Have compared some songs from youtube and my harddisk, actually the volume level from youtube is lower. Even if I download it from youtube it has higher level than online playback. I am using Linux Mint 20.3, the sound from PC goes out from USB XMOS transport, I saw this problem when PIP window was integrated in Opera, don't know is it present in previous versions of Opera, now I am with last official version and it is in.
I will be happy if someone can find solution of this problem.