If we compare 48:2 with 33:33 then do it not also prove infalliability for all those who are addressed there?
Both verses are similar where Allah swt is intending or desiring something with perfection.
[Malik 48:2] So that Allah may forgive your past as well as your future sins, and may perfect His blessings upon you, and keep you on the Right Way.
لِيَغْفِرَ لَكَ اللَّهُ مَا تَقَدَّمَ مِنْ ذَنْبِكَ وَمَا تَأَخَّرَ وَيُتِمَّ نِعْمَتَهُ عَلَيْكَ وَيَهْدِيَكَ صِرَاطًا مُسْتَقِيمًا
[Malik 33:33] (part of verse) O people of the household of Rasool, Allah only intends to remove uncleanliness from you and to purify you completely.
إِنَّمَا يُرِيدُ اللَّهُ لِيُذْهِبَ عَنْكُمُ الرِّجْسَ أَهْلَ الْبَيْتِ وَيُطَهِّرَكُمْ تَطْهِيرًا