aria2 launchd plist

homebrew.mxcl.aria2.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>EnvironmentVariables</key>
    <dict>
       <key>LC_MESSAGES</key>
       <string>C</string>
    </dict>
    <key>Label</key>
    <string>homebrew.mxcl.aria2</string>
    <key>ProgramArguments</key>
    <array>
        <string>/opt/homebrew/bin/aria2c</string>
        <string>--rpc-secret=YOUR_RPC_SECRET</string>
        <string>--enable-rpc</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>KeepAlive</key>
    <true/>
</dict>
</plist>

Copy to /opt/homebrew/Cellar/aria2/VERSION/