I agree! Thx for asking. I don’t get a proper one.

$ sudo systemctl start caddy 
Job for caddy.service failed because the control process exited with error code.
See "systemctl status caddy.service" and "journalctl -xeu caddy.service" for details.

$ journalctl -xeu caddy.service 

May 18 09:28:45 username caddy[6163]: caddy.AppConfigDir=/var/lib/caddy/.config/caddy
May 18 09:28:45 username caddy[6163]: caddy.ConfigAutosavePath=/var/lib/caddy/.config/caddy/autosave.json
May 18 09:28:45 username caddy[6163]: caddy.Version=v2.10.0 h1:fonubSaQKF1YANl8TXqGcn4IbIRUDdfAkpcsfI/vX5U=
May 18 09:28:45 username caddy[6163]: runtime.GOOS=linux
May 18 09:28:45 username caddy[6163]: runtime.GOARCH=amd64
May 18 09:28:45 username caddy[6163]: runtime.Compiler=gc
May 18 09:28:45 username caddy[6163]: runtime.NumCPU=4
May 18 09:28:45 username caddy[6163]: runtime.GOMAXPROCS=4
May 18 09:28:45 username caddy[6163]: runtime.Version=go1.24.2
May 18 09:28:45 username caddy[6163]: os.Getwd=/
May 18 09:28:45 username caddy[6163]: LANG=en_US.UTF-8
May 18 09:28:45 username caddy[6163]: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
May 18 09:28:45 username caddy[6163]: NOTIFY_SOCKET=/run/systemd/notify
May 18 09:28:45 username caddy[6163]: USER=caddy
May 18 09:28:45 username caddy[6163]: LOGNAME=caddy
May 18 09:28:45 username caddy[6163]: HOME=/var/lib/caddy
May 18 09:28:45 username caddy[6163]: INVOCATION_ID=2fc1e0f2649a41a69ae54fe267fa0bc5
May 18 09:28:45 username caddy[6163]: JOURNAL_STREAM=9:41227
May 18 09:28:45 username caddy[6163]: SYSTEMD_EXEC_PID=6163
May 18 09:28:45 username caddy[6163]: MEMORY_PRESSURE_WATCH=/sys/fs/cgroup/system.slice/caddy.service/memory.pressure
May 18 09:28:45 username caddy[6163]: MEMORY_PRESSURE_WRITE=c29tZSAyMDAwMDAgMjAwMDAwMAA=
May 18 09:28:45 username caddy[6163]: SYSTEMD_SLEEP_FREEZE_USER_SESSIONS=0
May 18 09:28:45 username caddy[6163]: {"level":"info","ts":1747553325.945979,"msg":"maxprocs: No GOMAXPROCS change to reset"}
May 18 09:28:45 username caddy[6163]: Error: reading config from file: open /etc/caddy/Caddyfile: permission denied
May 18 09:28:45 username systemd[1]: caddy.service: Main process exited, code=exited, status=1/FAILURE
░░ Subject: Unit process exited
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░ 
░░ An ExecStart= process belonging to unit caddy.service has exited.
░░ 
░░ The process' exit code is 'exited' and its exit status is 1.
May 18 09:28:45 username systemd[1]: caddy.service: Failed with result 'exit-code'.
░░ Subject: Unit failed
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░ 
░░ The unit caddy.service has entered the 'failed' state with result 'exit-code'.
May 18 09:28:45 username systemd[1]: Failed to start caddy.service - Caddy.
░░ Subject: A start job for unit caddy.service has failed
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░ 
░░ A start job for unit caddy.service has finished with a failure.
░░ 
░░ The job identifier is 3809 and the job result is failed.

$ sudo systemctl status caddy                 

× caddy.service - Caddy
     Loaded: loaded (/usr/lib/systemd/system/caddy.service; enabled; preset: disabled)
    Drop-In: /usr/lib/systemd/system/service.d
             └─10-timeout-abort.conf, 50-keep-warm.conf
     Active: failed (Result: exit-code) since Sun 2025-05-18 09:32:18 CEST; 4min 37s ago
 Invocation: b2e02d16f6614d5fb85f54a67bce414a
       Docs: https://caddyserver.com/docs/
    Process: 6930 ExecStart=/usr/bin/caddy run --environ --config /etc/caddy/Caddyfile (code=exited, status=1/FAILURE)
   Main PID: 6930 (code=exited, status=1/FAILURE)
   Mem peak: 16.4M
        CPU: 66ms

May 18 09:32:18 username caddy[6930]: JOURNAL_STREAM=9:49675
May 18 09:32:18 username caddy[6930]: SYSTEMD_EXEC_PID=6930
May 18 09:32:18 username caddy[6930]: MEMORY_PRESSURE_WATCH=/sys/fs/cgroup/system.slice/caddy.service/memory.pressure
May 18 09:32:18 username caddy[6930]: MEMORY_PRESSURE_WRITE=c29tZSAyMDAwMDAgMjAwMDAwMAA=
May 18 09:32:18 username caddy[6930]: SYSTEMD_SLEEP_FREEZE_USER_SESSIONS=0
May 18 09:32:18 username caddy[6930]: {"level":"info","ts":1747553538.0326045,"msg":"maxprocs: No GOMAXPROCS change to reset"}
May 18 09:32:18 username caddy[6930]: Error: reading config from file: open /etc/caddy/Caddyfile: permission denied
May 18 09:32:18 username systemd[1]: caddy.service: Main process exited, code=exited, status=1/FAILURE
May 18 09:32:18 username systemd[1]: caddy.service: Failed with result 'exit-code'.
May 18 09:32:18 username systemd[1]: Failed to start caddy.service - Caddy.

Buying a new keyboard with an unusual key (combination) is not the solution to a universal copy paste shortcut. I didn’t get why you’d write about adding a new universal shortcut by buying a new external keyboard that you can customize when you can customize what you already have. Yes, customizing the external keyboard is different but it is far far away from becoming universal.

I got bored after reading 95%, including the end, and it does not mention what the “new” keyboard shortcut is.

I also miss the point why you bring up external programmable keyboards and not mentioning alternative layouts like neo.