You might use:
A free online recorder like: https://www.apowersoft.com/free-online-screen-recorder
I run it direct from the web = click the “Start Recording” button. You can make it capture the screen and audio or just audio.
There’s sometimes a little bit of fiddling to get the Syrinscape Audio heard by Apowersoft, but once it’s working, it works really well. HINT: open Apowersoft, record a little bit of audio and then stop it again, THEN start Syrinscape, and you should be good to go. You’ll need to let Apowersoft install the virtual audio driver on your system. IMPORTANT: Always test it's recording correctly before you do something long and significant.
Audacity, it’s just a matter of working your way through one of the many reasonably helpful, but often slightly confusing tutorials you can find online. Like here: https://manual.audacityteam.org/man/tutorial_recording_computer_playback_on_windows.html
OBS
Or run Syrinscape on a phone or tablet and plug the headphones into a stereo input on any recording device
Something else we haven't thought of yet!