Their answer comes from a narrow interpretation of bhakti, which they hold to be only a one-pointed involvement in one thing and nothing more.
RupaM is inherent nature.
Tat-tvam is also the same.
In fact it is ‘tat-tvaM’ that directly means ‘inherent nature’.
However, ‘sva-svarUpa-anusandhAnaM’ has an implied sense of internal dissolution of the individual soul in the Universal source, which sense seems to be absent in ‘svAtma-tattva-anusandhAnaM’.
It looks as if some inaccessible principle is being experienced from a distance.