After the death of Isshiki Otsutsuki, Code rose to the top of the antagonists left in Boruto: Naruto Next Generations. Inheriting the will of the Otsutsuki and swearing vengeance upon those who played a part in Isshiki's fall, Code became extremely powerful after having his limiters removed by Amado.
Currently, he is most likely the strongest character alive in Boruto and while nobody can win against him in combat just yet, there are quite a few who can, at the very least, put up a fight against him.
7 Kashin Koji
-2.jpg?q=50&fit=crop&w=1500&dpr=1.5)
Kashin Koji is one of the former members of Kara and ranks among the very strongest people in the world of Boruto. Thanks to Amado's modifications, Koji has been made a very powerful being. He is the genetic template of Jiraiya, meaning everything that Jiraiya could do he can do better since he's been modified accordingly. In the fight against Jigen, Kashin Koji showed his worth, and even against Isshiki, he was able to hold his own for a while. Although he certainly can't defeat Code, taking him on in combat for an extended period of time certainly seems possible for him.
6 Naruto Uzumaki
After losing the powers of Kurama, Naruto Uzumaki has significantly weakened. However, that's not to say that he is weak. Naruto still has the power of the other Tailed Beasts within him, along with the ability to use Sage Mode. His strength is more than enough to take on figures such as the Kara Inners without even relying on Kurama's power. While Naruto certainly cannot defeat Code as he is and, in an extended combat, would most certainly die, he can still take him on in battle and impress. This is something the fans could see in the future if Code decides to attack Konoha.
5 Sasuke Uchiha
-2.jpg?q=50&fit=crop&w=1500&dpr=1.5)
Just like Naruto Uzumaki, Sasuke Uchiha has also been significantly weakened after Boruto, while being possessed by Momoshiki, stabbed his Rinnegan. Sasuke still has great strength up his sleeve and would most certainly be able to take Code in combat if the need ever arises.
He has the power of the Eternal Mangekyo Sharingan at his disposal, along with powerful abilities such as the Susanoo and the Forbidden Jutsu such as Izanagi and Izanami. Sasuke has a mastery of all the nature types and for him, taking on Code in an extended fight should be possible. Defeating Code, however, is a different thing altogether.
4 Boruto Uzumaki
Currently, Boruto Uzumaki is one of the strongest characters in the Boruto series. After gaining control of the second stage of his Karma, Boruto has ascended to a level where he can take on most characters in the story. He has already fought Code before and did extremely well against him in combat. After being Outsutsukified completely, he will likely have gotten even stronger. His strength would still be less than that of Code currently, however, for him, taking him on and combat, and even damaging him to quite an extent would be possible. With the experience of Momoshiki Otsutsuki and even the Dojutsu such as the Jogan, Boruto Uzumaki should do fairly well against Code.
3 Kawaki
Just like Boruto Uzumaki, Kawaki is also one of the most powerful characters in the story currently, perhaps even more than Boruto. Although Kawaki had rid himself of the Karma following Isshiki's death, Amado reconstructed the seal into him when he fixed his arm. To save Naruto, Kawaki summoned the power of the Karma once again and gained all the abilities of Isshiki Otsutsuki.
Just like Boruto, he can access level 2 of the Karma seal. He also has access to abilities such as Sukunahikona and Daikokuten, using which he can easily take Code on in combat. After having his limiters removed, Code would certainly be more powerful than Kawaki at the moment, however, with a bit more training, the latter will certainly able to put up a great fight against him.
2 Daemon
Daemon is one of the newly introduced characters in Boruto: Naruto Next Generations. Although he isn't a traditional fighter, he has a terrifying ability to reflect any damage thrown his way back to the user. This ability has been seen on several occasions, most recently when he reflected one of Kawaki's attacks back towards him and ended up knocking him out completely in the process.
Daemon can fare incredibly well against Code in regular combat and his ability to reflect any damage, even when he's not looking, is absolutely incredible.
1 Eida
Eida is one of the strongest characters in Boruto currently. She was created by Amado and was cast aside by Jigen because he feared her ability quite a bit. Eida has incredible combat ability, as indicated by Jigen's fear of her but her most lethal ability is to bewitch anyone regardless of their sexuality.
Eida has used this ability on several occasions and even the likes of Code are not safe from it. Her ability can only be countered by her blood relatives and those who possess Otsutsuki blood.