Okay so i have this item i homebrewed and i want some opinions on it, like is it to powerful or what not any advice is welcome and thanks!

Horn of The Dread

Legendary
Attunement: Yes
When you blow into one end of the horn no noise will be heard by you but everyone in the area will hear the most horrifying noise they can imagine.

1 Day Regains at Dawn

Effects:
When the person blows into the horn everyone in a 60 ft Radius must make a Wisdom Saving Throw(if its a DM controlled character using it its DC:22) (DC Equals 18+Players Proficiency Bonus) on a successful save they can't be frightened by the horn for 2 days on a failed save target if frightened for 2 minutes(12 Turns) and the *Dread Effect Happens.

*Dread Effect(Temporary Buff): for every creature Frightened increase all stats by 1 per creature frightened and for every 3 Creatures increase AC by +2 for 2 minutes(12 Turns)

OP., also 2 mins is 20 rounds not 12 6 x 10 is 60 so 1 min is 10 turns. Imagine having over at least 100 creatures in the same area but if its a few it is understandable, raising a creatures stats equal to +1 per frightened creature is strong as this may turn their to hit and con and all other stats to become complicated unless you are willing to complicate it. Cause you are taking in the constitution hit point modifier, to hit and attack damage bonus, spell dc and healing etc. But it makes sense that it lasts for a long time as to adjust it and revert it back  to normal after 2 mins of combat.

Make the dawn instead 7 days - 1 month recharge.

Okay thanks, is there anything else that could be changed/improved?

 Also should it be like 1d4 weeks it takes to recharge or just a set value?

Okay there hit dice wouldnt be affected, if a cleric has this horn and casts a healing spell the would use the con mod, spell dc would be increased by whatever your new stat is so on and so forth, also it does not count twords your AC unless it it the second part of for every 3 creature Ac increases by +2