FiveM docs on Ace permissions → Server Commands - Cfx.re Docs
FiveM docs on txAdmin permissions → undefined - Cfx.re Docs
Forum post with more detail on permissions → ACE Permissions
External docs on permissions → ACE Permissions - Badger Docs
You can make them an admin…
server.cfg:
add_principal identifier.steam:110000112345678 group.admin -- discord, steam, license, etc.
add_ace group.admin command allow
Or just grant that single permissions…
server.cfg:
add_ace identifier.steam:110000112345678 command.restart allow -- discord, steam, license, etc.