I am using Linux on my Lenovo Tiny PC with Solus OS and do not have any distortion issues at all. I also use NAD Wireless USB DAC 2 that’s connected via USB to my Lenovo and the other box is connected to my pre-amplifier. At the beginning the sound was okay but after sometime the sound did improve a lot (I guess burn-in effect). Also on Solus OS I installed Spotify app from their software repository and works amazing. I can also control App from my iPad or iPhone or Android phone. Everything works as it should ie. skip, changing the album, search function, etc.
Also depending on the player I am using I can specify what to use directly, speak, I can stream from player directly to NAD DAC but also using different connection for my PC output (this works only for music saved on hard drive but not for streaming) and sending the output to my Fostex small Studio Monitors. For streaming I have to use PC’s default output which can be configured in settings.
I do not have distortions anywhere.
With NAD USB DAC 2 I have eliminated the wires as this is point-to-point wireless solution without need for wifi. Works very, very reliably and since they one I never had failure or any troubles.
The only thing that I have to do if I like to stream from PC is to change the sound output from Settings to NAD instead to speakers. That’s all.
I hope that this will contribute to your troubleshooting but I as someone stated before it is likely the combination of the hardware and software you are using.
P.S. I did try Zorin OS but it was so buggy and I had always issues with that OS. Ubuntu was much better as well as Mint. I did like Fedora but ultimately I settled for Solus OS (using gnome but previously used Solus OS Budgie) and is working without any hiccups since I installedIt, I think 5-6 years ago. I did full reinstall around 1-2 years ago but I did change my hybrid HD (combination of SSD+HDD) to SSD and did clean install instead of moving the installation to new SSD and I always recommend to do full clean install of OS.
Since you have DELL laptop you can experiment with it and try some other distros as Zorin OS may be also not prefect. Try Debian, Ubuntu, Fedora, Mint, and others... Just my 2c.