Severely distorted audio via Displayport

I have an Intel based mobo, the audiojack performs fine.
But the connected Lenovo P24h monitor (via Displayport) has an audiojack too, which is way more convenient to use.

Unfortunately, speech volume is low and distorted, overall audio is distorted and after a reboot it starts a bit bad but becomes worse quickly. Overal volume is low.

I tried the 2 suggestions mentioned here:

sudo leafpad /etc/pulse/

If you are using line numbers it is roughly line 53:

Original line...
load-module module-udev-detect
Added to the end of this line was tsched=0
load-module module-udev-detect tsched=0

Also tried tsched=1

Then I tried the other option, changing sampling rate in a config file. After both attempts I did killall pulseaudio; pulseaudio -k

But it didn’t matter. The issue remains. Any ideas?

I use this monitor for work now and especially speech is too distorted and low volume, cannot use it like that.

EDIT: also happens when connecting via USB-C (instead of Displayport, but I guess it is the same signal) to an AMD Ryzen 4800 laptop.