Not a solo as I cruise with DW, but I totally understand what you wrote about finding a shared table. Our last NCL cruise was on the Epic in the Western Mediterranean 10 years ago. On the first night at dinner, we were asked do you want a table for 2 or to share a table. We replied that we would share as we have often enjoyed meeting others at dinner. And then after we were seated, we waited, and waited, and waited. We finally realized no one else seemed to want to share, and then said we would do a table for 2.
After we booked an NCL cruise again (the Prima next summer), I posted and asked if this was typical. The overwhelming majority of posters wrote basically why would I ever want to share a table with strangers.