BTW MacOS Big Sur didn't need a driver for the Behringer Line 2 USB but Windows 10 users will need to install the ASIO4ALL driver software (linked from the Behringer product page too).

Here's my review of the Behringer Line 2 USB.
Sound quality is excellent. Background noise is very low. Nice and quiet.
I have my Sylphyo set to the default sound volume (80%) so I guess that the synth engine in the Link is also at 80%? There is plenty of audio level.
The Mac mini M1 sees the Behringer as "USB PnP Audio Device". To ensure that I do not get clipping, the input level is at 25%. The volume in my Focal XS 2.1 speaker system is similar to the output from the Respiro software synth.
I am using Apple GarageBand. The Behringer is set as a stereo line input ("Monitoring" set to "on"). I'm not noticing any latency.
When I took an output from the Link's headphone socket directly into the Focal XS 2.1 speaker system's audio input, I was picking up some audio hum (not loud but annoying) so the quiet background of the Behringer solution via the Link's audio outputs and the Mac, is much better. With the input into GarageBand, I can also record and review my practicing. Which is a helpful bonus.
Overall, I'm very impressed as were some folks on Sweetwater.
The Behringer Line 2 USB does exactly what I want.

Thank you for the information, Maxence and Clint.
I bought the cable yesterday. I should receive it today.
I figured that it was worth giving it a try as it was relatively inexpensive at £17.99 (€21, $25 USD) including carriage.
I do not have two mono ¼" (6.35mm) jack cables to hand, to connect between the Sylphyo Link's Line Out sockets and another USB audio interface/mixer so the all-in-one nature of the Behringer Line 2 USB appealed to me.
I will post again when I have tried the interface cable to give my impressions on it and whether it works with the Sylphyo Link and an Apple Mac mini M1.

I want to connect the audio output of my Sylphyo LINK to my Apple M1 Mac mini so I can hear the sounds from the internal synth via my Focal XS computer speaker system. The M1 Mac mini has no audio input jack.
The Sylphyo LINK is powered from the Mac via the mini USB power supply port. The same cable allows me to control the excellent, Respiro soft synth with the Sylphyo but I would like to be able to hear the Sylphyo LINK's internal synth sound universes too.
I have found the Behringer Line 2 USB Stereo 1/4" Line In to USB Interface Cable. Would this allow me to hear the Sylphyo LINK's sound universes with my computer speaker system?
I would connect the USB A plug of the Behringer Line 2 USB into my Mac and the left and right mono ¼" (6.35mm) jack plugs into the LINK's Line Out sockets.
I have Garage Band and also Apple MainStage.
Any other audio input solution suggestions for the M1 Mac mini would be welcome too?