Is it better, after performing the rituals of Umrah, to perform another Umrah for a deceased father, or to repeat the circumambulation (Tawaf) with every visit to the Haram? And is looking at the Kaaba an act of worship?

Performing circumambulation (Tawaf (definition)) extensively is better than performing Umrah (definition) on behalf of the father, due to the great reward mentioned concerning the virtue of Tawaf. Furthermore, it has not been reported that the Companions and the Salaf performed Umrah on behalf of their deceased during the same journey. It is more fitting to engage in Tawaf and increase supplication and seeking forgiveness for the father, while still permitting performing Umrah on his behalf after performing Umrah for oneself. As for looking at the Kaaba, it is considered an act of worship by some scholars, but the narrations regarding its virtue have weak chains of transmission.