Custom SSH Agent doesn't work with Xcode

Short description:

I cannot use my SSH key stored in my password manager Bitwarden to sign my Git commits via Xcode.

Background:

I am using Bitwarden to manage my SSH keys. Basically I have this line in my ~/.zshrc file:

export SSH_AUTH_SOCK=/Users/username/Library/Containers/com.bitwarden.desktop/Data/.bitwarden-ssh-agent.sock

And this is a part of my Git config:

user.signingkey=ssh-ed25519 mykey myemail@xxx.com
gpg.format=ssh
commit.gpgsign=true

This makes sure Git will use sign my commits with the key that I specified. However, the key doesn't really live in my ~/.ssh folder. It lives in my Bitwarden vault. That's why I need to set up that custom SSH Agent to make sure git will be able to sign my commits.

When I run git commit in terminal, my Bitwarden will ask me to approve the usage of my key like this:

If I authorise, my commits will be successfully signed.

Issue:

When I try to commit in Xcode. Xcode isn't really using my custom SSH agent defined in my .zshrc file, as a result, Xcode cannot find my specified SSH key in my Git config, and there will be an error like this:

Workaround:

I have noticed that if I launch Xcode from my terminal like this:

open -a Xcode

There won't be any issue. Bitwarden will ask approval from me, and I can authorise it. Everything works just fine. I suppose this is because launching Xcode from the terminal will inherit environment variables from my .zshrc, whereas launching Xcode directly will not.

Something that I have already tried:

I have tried to set up my SSH_AUTH_SOCK again in launchd agent again like this:

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
 "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>Label</key>
    <string>environment.ssh</string>
    <key>ProgramArguments</key>
    <array>
      <string>launchctl</string>
      <string>setenv</string>
      <string>SSH_AUTH_SOCK</string>
      <string>/Users/username/Library/Containers/com.bitwarden.desktop/Data/.bitwarden-ssh-agent.sock</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
  </dict>
</plist>

After this I have rebooted my mac. Unfortunately, this doesn't really work either.

How can I get this to work normally? I don't want to launch Xcode from terminal all the time, but I do want it to work with my password manager.

[Edited by Moderator]