The Cambridge Grammar of the English Language in its section (p1506) on anaphoric uses of this and that with noun phrases as antecedents states:
... both this and that can be used anaphorically - and in general one
could be replaced by the other with very little effect on the meaning.
In contrast, Swan in Practical English Usage (p591) does detect a slight difference:
This is preferred when there is more to say about the new subject of
discussion:
"Then in 1917 he met Andrew Lewis. This was a turning point in his
career: the two men entered into a partnership that lasted until 1946,
and ..."
(More natural than ... "That was a turning point ...")
It is likely that the OP's sentence will be followed by something more on the new subject (academic eagerness). For example:
It is true that I wrote critical and analytical essays on a regular
basis; this, however, did not satisfy my academic eagerness. I also
engaged in research ... etc.
Thus if we follow Swan, this is to be preferred to that in the context of the OP's sentence.
This, as the more present or proximal pronoun, may also better convey the sense that what is being referred to is relevant in the present context (for example, an application letter or cv). So, in the context I have assumed for the OP I would use this.