Hi
I've just got the G8JCFSDR working completely properly on a Raspberry Pi 4 running Buster - see Screenshot - :-)

Before you install wine etc, you need to make sure that you have a proper working and configured ALSA audio system on your RPI. The RPI doesn't have an onboard soundcard so an external? USB soundcard is required, I used an ASUS XONAR 7, but I have also managed to get a Creative X-Fi working, but it was nowhere as easy as the ASUS XONAR. Once you have got a correctly working audio setup, you can proceed to installing wine, g8jcfsdr etc, ie there's no point in trying wine etc until there is a working LINUX ALSA setup.
The "secret sauce" to making wine(x86) work consistenly on my RPI was to use pi-apps, , wget -qO- https://raw.githubusercontent.com/Botspot/pi-apps/master/install | bash installs pi-apps itself, then run pi-apps and install wine(x86). The pi-apps way of installing wine(x86) will install box86 and a whole load of dependencies, dlls, and other vital stuff in addition to wine itself. I had tried the more usual methods of installing wine(x86) on the rpi manually, but it was always hit or miss if things worked properly, but with the pi-apps method it just works !! If you use the usual sudo apt install wine method, you will install wine(armhf) which will only run Windows programs written for ARM processors which is not what is needed here, and indeed there are very few Windows programs compiled for ARM afaik.
After pi-apps has finished - it took at least 15 mins for me over 12 Mbit DSL - the first thing to do is set the sound configuration for wine to ALSA using either the winetricks gui or in a terminal type
winetricks settings sound=alsa
For some reason the default sound setting for wine is pulseaudio which just doesn't work for pretty much anything - rant over, it took me 4 hrs to figure out why nothing seemed to work - audio wise - under wine
Then download the G8JCFSDR setup from? This build has support for LINUX based environments.
Run the setup program and follow the onscreen instructions.
The main difference between the standard Windows installer and the LINUX installer is the addition of a step to add the user to the dialout group - required for access to serial ports, and then mapping LINUX serial ports, eg /dev/tty0 to wine COM ports, eg com16, after that the standard windows installer is run.
Once the installer has finished, you should be able to run the G8JCFSDR and do all the usual stuff to configure, calibrate and other actions just as you would for a windows environment.
My next step is to get a small 7 in TFT touch screen for my rpi, and box it all up to make a standalone small communications receiver - complete with proper tuning knob !!
I would be interested if someone else can give this setup a tryout and let me know if it works for them - btw this should also work on an RPI 3B+
73
Peter - GM8JCF