Thank you for responding, Ricardo! I have tried several permutations of packages, but currently I have this:
$ guix package --list-installed
guile 3.0.8 out /gnu/store/1jgcbdzx2ss6xv59w55g3kr3x4935dfb-guile-3.0.8
gnutls 3.7.7 out /gnu/store/349nw48785mbxzsl3adc4wch1hslg7fl-gnutls-3.7.7
guile-g-golf 0.1.0-1010.1824633 out /gnu/store/vwkaxl1cl76yxdpzvkvx0sclkyksqm9g-guile-g-golf-0.1.0-1010.1824633
I am a complete n00b with guix (and g-golf, but I have some history with guile), so I'm assuming I'm doing things incorrectly. That's why I'm trying permutations of package installs; I get the same errors with gtk 4.6.6 installed and included on the guix shell command. So I'm willing to try whatever you suggest, to get this bug closed. My base OS is Ubuntu 22.04, which only lets me install guile 3.0.7 via apt, and the other packages are similarly out-of-date or broken - which is why I turned to guix. It has done well on the other packages I've tried (gnutls, for one). So please tell me if I can help in any way.