Game mechanics wise, forcing a caster to use TWO 4th level spell slots (SGD and Charm Monster) and TWO Turns to try to get the demon to follow orders longer (and thus not kill your team) when it has one turn in between these actions to save and break free is overly punitive. Most fights are over in a few rounds. Even if the caster gets its name, it will still break free often times before the end of the battle (see an advantage, straight roll, disadvantage table, plug in the cha modifier and magic resistance trait). It will never last a full hour since it can make a save multiple times a minute depending on how many are in initiative. Plus, some of them have a 30% chance to summon another demon as an action. Think in terms of action economy. Getting a demon out, chance to save, charm (which can fail) is not fun. The player is losing out on doing everything else only to get something they will statistically lose control over shortly.
The widespread number of punitive interpretations of this spell make it not worth bothering with. Run it as written and don't bring in rules from other places. The spell is the specific rule, and it doesn't say anywhere that it should take an action to give you the name:
Player characters can say things in battle for free and take actions too. Why is the demon treated differently? It has its own initiative and should be given the same combat criteria as players who can yell "help" or "over here" or "the Wall is an illusion" while also casting a spell or swinging a maul two times and moving 30 feet. Familiars get this treatment.
Commanding it to give you its name first should be protocol or the spell is junk and nothing more than a stink bomb, in which case you're safer casting sickening radiance or any other persistent area of effect that do more damage and that you maintain control over.
DMs making it an action or have an extra save or requiring charm or having the cleric in your group throw a fit and call you evil are all ways to make people pass this spell up or leave the table. Putting all these unwritten rules into the spell ruins it.
It is there so you can access a sack of hit points (less reliably than say Summon Shadowspawn, a lower level spell), acquire access to spells at lower save DCs (watch out for that DC 12!) you may not otherwise have or increase your spells known economy at a risk, and do a little damage if you get the barlgura out, whose attacks aren't even magical, which is a big deal by the time you get this spell.
Tldr: it can say it's name if commanded on the first turn, and it doesn't take an action because players can say things too without taking an action. The spell does not state it makes a save at that time either. It only makes a save at the end of the demon's turn. More punitive interpretations make the spell horrible. It is a cool spell. Let it play. It's not going to wreck the game.