Is it beneficial for a repentant person to frequently seek forgiveness, pray, and give charity to expiate a continuous sin that they cannot stop committing?

One must beware of persisting in sins, for this can lead to Allah sealing the heart of the sinner, as stated in the Hadith: "Indeed, when a believer commits a sin, a black spot appears on his heart. If he repents, ceases, and seeks forgiveness, his heart becomes polished. But if he increases [in sin], it increases until it covers his heart, and that is the 'Rān' (stain) which Allah the Almighty mentioned: 'Nay! But on their hearts is the Rān (stain) which they used to earn.'" Sincere repentance to Allah and adherence to His law are obligatory, along with seeking His help, for indeed, good deeds erase evil deeds.