Yubikey smartcard & challenge mode usable on remote ssh

After some debugging with journalctl -xe and some googling i found that will be a nightmare :

2020-09-09 21:43:06 scdaemon[2795] pcsc_list_readers failed: unknown PC/SC error code (0x8010002e)

But normally, as they said here (gpg fails to use yubikey · Issue #85127 · NixOS/nixpkgs · GitHub) we don’t need pscv activated, so if i desactivate, i have this (no service … yes i know, i desactive it ) :

2020-09-09 21:59:48 scdaemon[3326] pcsc_establish_context failed: no service (0x8010001d)

OK, whatever, the problem seem linked to FW agent which doesn’t work for other thing than ssh-add, i add some new things :

REMOTE gpg.conf

use-agent

LOCAL gpg-agent.conf

extra-socket /home/myhome/.gnupg/S.gpg-agent-extra
debug-level guru
debug-all
log-file /tmp/gpg-agent.log

I also try manually using :

ssh -A myremotehost -R /run/user/0/gnupg/S.gpg-agent:/home/myuserhome/.gnupg/S.gpg-agent

Will try this tomorow : How to get the best out of your Yubikey with GPG - Cal Bryant

Perhaps someone, like @srhb could help me by sharing part of their nix ?

This is wtf.