Save DC 8 + proficiency + charisma. Duration 1 minute. Charisma save at the end of turn.

Hostile creatures that fail a charisma save against being taunted have disadvantage against targets other than you. A target is immune to this effect if it can't see or hear you.

Well, take a look at the Kender’s Taunt trait:

Taunt

You have an extraordinary ability to fluster creatures. As a bonus action, you can unleash a string of provoking words at a creature within 60 feet of yourself that can hear and understand you. The target must succeed on a Wisdom saving throw, or it has disadvantage on attack rolls against targets other than you until the start of your next turn. The DC equals 8 + your proficiency bonus + your Intelligence, Wisdom, or Charisma modifier (choose when you select this race).

You can use this bonus action a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

That requires a bonus action to activate, only targets a single creature, only imposes disadvantage for 1 round, and they can only use it a few times per day. Yours is always on, works against all creatures, and lasts for a minute, and has infinite uses. That’s more powerful than the compelled duel spell which also requires a bonus action to activate, only targets a single creature, lasts for up to a minute but also requires concentration, and burns a spell slot to use it. Yeah, I’d say that by comparison yours is a little OP.

Thank you for you feedback, i will try to fix it as best i can

hopefully this fixes the brokenness of this feat:

Save DC: 8 + proficiency + charisma. Uses: equal to half Proficiency bonus. Duration: a number of rounds equal to your Charisma Modifier. Targets: a number of creatures equal to your charisma modifier. Save at the end of turn.

As a Bonus Action you can taunt creatures and cause then to make a charisma saving throw creatures that fail against being taunted gain a negative to their attack roll, equal to half your proficiency bonus, against targets other than you, a creature can repeat the saving throw at the end of its turn. A target is immune to this effect if it can't see or hear you.

At level 15 the number of creatures you can target includes your proficiency bonus, at level 20 the negative equals half your level.

That's a reasonable type of broken.

Please allow me to reword that for you and make a few tweaks:

As a Bonus Action you can taunt a creature that can see or hear you. A taunted creature must succeed at a Charisma saving throw or it suffers a penalty to its attack rolls against creatures other than you for a number of rounds equal to your Charisma modifier. The penalty equals half your proficiency bonus (rounded down). A creature can repeat this saving throw at the end of each of its turn, ending this effect on itself on a success. You can use this feature a number of times equal to your proficiency bonus, and regain all uses whenever you finish a long rest.

Starting at 15th level you can taunt a number of creatures equal to your Charisma modifier. At 20th level the penalty a taunted creature suffers to its attack rolls against other creatures is equal to your proficiency bonus.

That’s a reasonable type of broken.

Thank you for your feedback.

Yeah, that's better than it was before I believe.