Have you tried downloading Equalizer APO and using it for your headphones?

If you have not, google Equalizer APO and give it a try. There’s plenty of videos on the internet on how to download and use it - it is pretty simple. It does help with issues of low headphones sound on windows 10. If you will be trying it, don’t forget to restart your computer once the software is downloaded.

Let me know if it helped.

get a new pair / return them. if you tried all that, they sound shot

Put them in a jar of rice.