How can one dream of being with the righteous in Paradise and advising people after having intentionally committed masturbation, despite repenting again?

One must worship Allah for His own sake. The sweetness of obedience comes from performing good deeds (Ihsan). If this sweetness is lost, it could be a test or a door to supplication, coupled with the necessity of diversifying acts of worship. Returning to sin requires sincere repentance accompanied by good deeds, and not despairing of Allah's mercy. Enjoining what is good and forbidding what is evil is an obligation that is not waived by committing sins; it is among the reasons for steadfastness in righteousness. One should also be wary of means that lead to sins.