Any effort for good, when done in sync with the efforts of Rasulullah (S.A.W), is acceptable in the eyes of Allah.
Finality of prophethood implies that the responsibility of the prophetic efforts of dawah, trickles down to each member of the Ummah. These efforts, when done inline with the efforts of Prophet PBUH, will result in the promised hidayah (guidance).
وَٱلَّذِينَ جَـٰهَدُوا۟ فِينَا لَنَهْدِيَنَّهُمْ سُبُلَنَا ۚ وَإِنَّ ٱللَّهَ لَمَعَ ٱلْمُحْسِنِينَ.
As for those who struggle in Our cause, We will surely guide them along Our Way. And Allah is certainly with the good-doers. -Qur'an (29:69)