• https://docs.ankiweb.net/sync-server.html

This works as of 2023-07-18

• Get a version of Anki equal to or later than 2.1.57
• Unpack it to /opt/anki
• Create a systemd service called anki.service:

snippet.ini

[Unit]
Description=Anki
 
[Service]
ExecStart=/opt/anki/anki-<version>-linux-qt6/anki --syncserver
WorkingDirectory=/opt/anki/anki-<version>-linux-qt6
Environment="SYNC_USER1=<username>:<password>"
Environment="SYNC_PORT=<something other than 8080>"
Environment="SYNC_BASE=<directory to store databases>"
 
[Install]
WantedBy=multi-user.target

• Install a release of 2.16.0 of AnkiDroid. Right now, those are all betas: https://github.com/ankidroid/Anki-Android/releases
• Set the sync server to be your internal server:port
• Log in using the username and password
• Sync your local data to AnkiWeb