Being stronger than Teen Naruto and Sasuke doesn't mean you can beat Adult Naruto and Sasuke, there's no reason to believe they got weaker and they'd have to be braindead to not get stronger
It was even confirmed by Kishimoto that Naruto & Sasuke had gotten a lot stronger since Shippuden that they had to scale fights down to not overshadow the new generation in Boruto Part 1 (Boruto, Sarada, Mitsuki, etc.)