も結構です

I don't need that either

→ も
phrase Uncommon #13,321
I don't need that either A polite way to decline an additional offer or item. 結構です can mean “no, thank you” or “that's enough,” and も adds “also” or “either.”
JA: お水はもう結構です。コーヒーも結構です。
EN: I don't need any more water. I don't need coffee either.

そこに入って座っても結構です

You may enter and sit there.

もう結構デザートも結構です

No more, thank you—not even dessert.

もう結構食事も結構です

No more, thank you—I’ve had enough to eat.

結構ですも結構です

No, thank you. Nothing else, either.

もう結構ですお茶も結構です

No more, thank you. No tea either.

結構です追加も結構です

No, thank you. I don't need anything else either.

幸せと思って不幸と思っても結構です

You can think of it as happiness or unhappiness—either is fine.

— 燃ゆる女の肖像 (2019)

もう結構それも結構です

No more, thank you. That’s quite enough.