I consider attendance at the novus ordo like attendance at a service of materially heretical Protestants.
In general, neither group is there to deliberately engage in heretical or demonic worship. For a few Catholics, those whom you know who truly have the Faith, but have yet to discover or have access to traditional Mass, I sit with family or friends and pray from my own missal. I definitely draw the line regarding communion or being a sponsor or the like.
Example, I prayed the Rosary with everyone else at my grandmother’s funeral Mass. She was 102. Regardless of it being a novus ordo, she knew and practiced the Catholic faith better than most who today call themselves traditional. At the time, 2001, I had never heard of tradition except as an historical entity. If I went to church at all, it was to whatever Protestant church I was ‘checking out’ in search of God. I’d given up on the Catholics by the mid-1970s. Despite the disdain of many Protestants for the Rosary or anything to do with Mary, I had an attraction to it and Her that I kept to myself for decades.
I did the same at the novus ordo funerals of my Uncle and Aunt, both of whom had the Faith. By then, 2009 and 2013, I had “discovered” tradition. At a Confirmation, a Baptism, and two more novus ordo funerals of non-family members who I didn’t know very well, I did exactly as I’d do at a Protestant service, sat towards the back, present out of professional obligation or respect, and silently prayed the Rosary or sat quietly.