How do I show related nodes as attachment in the term view block?
To insert one view into another (and pass arguments) as a field use Views Field View module. 

You'll have to use Has Taxonomy term ID Contextual filter in your Content Study Views, as No Sssweat suggested in comments, but you only need to choose the option to load it from the term page (not node page). And you don't need the additional ID Contextual filter for any exclusion (because you're not displaying it on node pages). 

Then include that Content View as a Field on your Term View, it will automatically filter out correct Studied on each Term row.