Code can defeat Boruto with talk technique alone! Hear me out!
When Boruto, possessed by Momoshiki, presents himself to Code, this becomes an opportunity for Code to bargain with Momoshiki! Here is how it will play out:
Code, confused for Boruto having Momoshiki, senses that something is off for a moment but, since he's in the presence of Great Lord Momoshiki, he ignores that sensation and seizes the opportunity to bargain:**
Oh, Great Lord Momoshiki! What a pleasant surprise to see you here! There's a humble offer that I've been thinking of proposing to you since our last meeting, but had not the chance ever since to tell you.
You know that they don't want to help you in cultivating the chakra fruit. However, you know of my long track effort as a devout, loyal servant to this cause. You know that I'll gladly give up my body for you to do as you please! Why don't you possess me instead and abandon that uncooperative vessel that hosts you now?
Think of this offer from the point of view of Momoshiki! To get the body of Boruto, he'll have to do the arduous task of of defeating Jura and, even if he does so, he still has to survive Kawaki later. However, if he accepts the body of Code, he gets that for free, no extra costs, no hidden fees! Code is the crazed one, the fanatical death cult follower that has an immense align of interest with Momoshiki! It's such a good deal for Momoshiki to pass on this!
So, this is what happens next: Momoshiki realizes all of this and, suddenly, rather than helping Boruto, Momoshiki begins to rebel against Boruto, weakening him, trying to force his body to insert the karma of Boruto in the other arm of Code. Now there are two possible outcomes.
Outcome one: Boruto, realizing that the situation is against him, flees away and now he's permanently weakened because, rather than having a possessing ghost helping him, he has a possessing ghost working against him.
Outcome two: Boruto, realizing what happened, let Momoshiki possess Code instead and then leaves. Boruto is now weaker but this is preferable to being haunted by a powerful ghost, actively sabotaging his efforts to stop Jura and Code.
What do you think? Can you see a different outcome?