The verse is
34:50

Say, “If I am astray, the loss is only mine. And if I am guided, it is ˹only˺ because of what my Lord reveals to me. He is indeed All-Hearing, Ever Near.”

— Dr. Mustafa Khattab, the Clear Quran


Say, "If I should err, I would only err against myself. But if I am guided, it is by what my Lord reveals to me. Indeed, He is Hearing and near."

— Saheeh International



Firstly, the verse starts with “IF’‘.So It is not a definite condition at all.

Secondly, if Muhammadï·º would be wrong,then he could not have continued.

69:43-47

43 ۞    [It is] a revelation from the Lord of the worlds.
44 ۞    And if he [i.e., Muḥammad] had made up about Us some [false] sayings,
45 ۞    We would have seized him by the right hand;
46 ۞    Then We would have cut from him the aorta.
47 ۞    And there is no one of you who could prevent [Us] from him.
            — Saheeh International

But as my Holy Prophet Muhammad s.a.w.w had continued to preach the revelation of Allah, it means that infact, He was totally and absolutely right. He was guided by Allah’s revelation. The second condition mentioned in the verse was true for Prophet Muhammad s.a.w.w.


Another verse from Holy Quran,
27:79  So put your trust in Allah, for you are surely upon the ˹Path of˺ clear truth.

                — Dr. Mustafa Khattab, the Clear Quran

            So rely upon Allah; indeed, you are upon the clear truth.

                — Saheeh International



Note that, there is no IF or but in the verse mentioned above, but there is a word INDEED so it is the true condition that Prophet Muhammad ï·º was on clear truth and guided by Allah’s revelation.