Is the repentance accepted from someone who cursed God while not knowing whether he had reached puberty or not, then committed many sins such as sodomy, watching pornography, talking about sex, and masturbating, in addition to falling into a false oath, knowing that he has repented from all of that, regretted it, and resolved not to return, and does the verse apply to him: ﴿And We would not punish until We had sent a messenger﴾?

No matter how great the sin, Allah's pardon is greater, and His mercy is vaster. Turn to your Lord with sincerity and a sincere repentance, with remorse and a firm resolve not to return to the sin, for "the one who repents from sin is like one who has no sin." Allah the Almighty said: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'" Increase in performing good deeds that expiate sins, and associate with righteous people. As for the false oath (Yamin Ghamus), if you were aware of the prohibition of lying, you have sinned. However, with your repentance, Allah accepts your repentance, and according to the majority of scholars, there is no expiation for it.