Can Tawbah from major sins only be done through Salat-at-tawbah?

Tawbah is just repenting it is not bound to a salah called repentance salah. Imam Ibn Uthaymeen said: The hadith about the Prayer of Repentance is weak, but it has supporting narrations that indicate it has a basis—such as the hadith of ʿUthmān ibn ʿAffān (may Allah be pleased with him), when he performed ablution as the Prophet ﷺ did, and said: “Indeed, the Prophet ﷺ performed ablution like my ablution, then said: Whoever performs ablution like this of mine, then prays two rakʿahs without letting his mind wander, Allah will forgive him his past sins.” This hadith serves as supporting evidence that if a person performs ablution thoroughly and then prays two units of prayer, his past sins will be forgiven. Questioner: Is it called the Prayer of Repentance, Shaykh? Shaykh: No, it is not called the Prayer of Repentance; it is called the Sunnah prayer of ablution, but repentance can be achieved through it.