I did find an old one in my windows backup (before upgrading to W10) .. an older Focusrite USB driver dated 2016
The only Focusrite I owned back then was a 2i2, other than that yer on yer own whether to try it.

It has been here since 2016, so I only assume this is what you are after
http://masteringmatters.com/stuff/focusrite-usb-2-driver-2.5.1.zip

//backups are wonderful things

All that said, my gut says it is USB interrupts caused by *something*
I'd be looking for that Dell model in searches for USB issue, or Audio issue .. at least if this doesn't help.
I suppose it's possible something in the Dell simply doesn't play nice with the current drivers.
That's the only thing I found that may be what you are looking for.

Make your sound your own!
.. I do not work here, but the benefits are still awesome