CPU usage is probably way too high. Realtek runs off your CPU. It's why it's always been junk.

Get a Creative SoundBlaster or ASUS PCIE Sound Card that's modern model and then disable the Realtek.

or look into a USB DAC + AMP and it will have it's own quality chipset and not need some special driver.

Or use the HDMI on your GPU and output to a TV or Audio Receiver to use the Audio Codec built into your GPU. DP can do that audio as well, but not all DP Displays have an audio output on the display, or allows audio out from DP. But all the HDMI + DP on your GPU can output audio if you allow it and have supporting device to connect to.

Thanks for your answer. I fear I'm quite rubbish when it comes to hardware. What's bugging me is my computer worked fine for years without such issues. I even upgraded my RAM from 16 to 32gb thinking it would resolve the issue, but I wouldn't even know what a dedicated sound card changes exactly.
Anyway, in the meantime I disabled Realtek audio from device manager but it doesn't change anything... I don't think the USB DAC + AMP would work as I use wireless headphones and speakers. Maybe it's a bluetooth issue?

Have you tried to manually uninstalling the sound drivers (uninstall the device too for that matter and then reinstall) and go to the realtek website and look for the newest drivers? Might be some corrupted codec. Have you installed any audio software recently (could have also been a game)?

Originally posted by x:

Have you tried to manually uninstalling the sound drivers (uninstall the device too for that matter and then reinstall) and go to the realtek website and look for the newest drivers? Might be some corrupted codec. Have you installed any audio software recently (could have also been a game)?

Realtek no longer has stand alone drivers after around 2017 or so. You'll have to get that from the Dell support site > drivers and software for your model of PC

This could be that "Exclusive Mode" feature found in:

Windows Key + R

mmsys.cpl

Right-click the Playback device and click "Properties"

Go to the Advanced tab and unclick both options, if applicable, where it says "Exclusive Mode".

If this feature is/was turned on, this makes Windows unable to multitask multiple audio outputs properly. Turning it off is how we can play audio from multiple sources. Turning it on directs the system to only allow one application to play audio properly.

Let's hope it is that simple of a solution.

This issue is what we call in the music business, a bad hit.

what you can also do is look if the complete deletion of the audio drivers would work

ddu may be used primarily for videocard drivers but it can also be used for audio drivers
https://www.wagnardsoft.com/display-driver-uninstaller-ddu

afterwards you search the model of your motherboard on the internet and click the manufacturer's site then go to support then drivers and get your on-board audio drivers

this is also a option you can try if top does not work and none of the fixes the others sugest
https://forums.guru3d.com/threads/windows-line-based-vs-message-signaled-based-interrupts-msi-tool.378044/

read carefully this is not one of those programs that you can easily revert back what you have done

most newer cards are already set into msi mode some older cards can have a slight fps gain when set into msi mode hench why i know of this feature is due to having tried it

its up to you if you want to risk needing to either use system restore as mentioned in the post or reinstall windows if you screwed up

i mention this because in the past i saw forums were putting the audio driver into msi mode fixed audio problems similar to yours

Thanks for all your answers guys!
I tried to reinstall drivers from device manager then reboot windows. It didn't work.
I tried to unclick Exclusive mode. It didn't change anything I'm sorry to say.
I'll try to reinstall the drivers manually from the site and give you an update soon.