"I asked 'Aishah and Umm Salamah about which deed did the Messenger of Allah ﷺ like to do most. They said: 'Whatever he could do regularly, even if it was little.'"  

سُئِلَتْ عَائِشَةُ وَأُمُّ سَلَمَةَ أَىُّ الْعَمَلِ كَانَ أَحَبَّ إِلَى رَسُولِ اللَّهِ ﷺ قَالَتَا مَا دِيمَ عَلَيْهِ وَإِنْ قَلَّ  

"The most loved deed to the Messenger of Allah ﷺ was what he could do regularly." (Another chain) with similar meaning.  

كَانَ أَحَبُّ الْعَمَلِ إِلَى رَسُولِ اللَّهِ ﷺ مَا دِيمَ عَلَيْهِ حَدَّثَنَا بِذَلِكَ هَارُونُ بْنُ إِسْحَاقَ الْهَمْدَانِيُّ حَدَّثَنَا عَبْدَةُ عَنْ هِشَامِ بْنِ عُرْوَةَ عَنْ أَبِيهِ عَنْ عَائِشَةَ عَنِ النَّبِيِّ ﷺ نَحْوَهُ بِمَعْنَاهُ هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ