Is interest in a topic/concept/thought, a form of craving? Must we rid ourselves of interest too?
If so, how do we approach so many activities in daily life, that rely on interest? These activities include reading. How do you make an activity such as reading wholesome? How can it be made beneficial to the practice?
Interest in a topic can be craving (tanha). One of the six senses is the intellect and ideas are the sense-objects for the intellect. If a certain idea gives you pleasure, then you may be craving and even clinging to it. This is with respect to the craving to sensual pleasures (kama tanha).
Let's say you are an academic, and you take a keen interest in your field of expertise, and try to read more in order to deepen your knowledge, with the goal of becoming a full fledged professor one day. That's also based on craving, but this time the craving of becoming (bhava tanha). You want to become a professor.
Interest in a topic can be desire (chanda). Let's say you intend to learn the Dhamma (teachings of the Buddha) not because it's an intellectually pleasurable philosophy (or metaphysics) and not because you want to become a professor or scholar of it, but because you want to understand the path to the end of suffering. This is a positive desire.
In any case, if your craving or clinging or desire leads to breaking the five precepts, then you must overcome it.
If your craving or clinging or desire leads to emotions that are based on the three poisons, then it is also skillful or wholesome to overcome it, before it causes you to commit bad kamma. For e.g. you like something, but someone prevents you from getting it, and this causes you to become angry and maybe cause you to attack this person. It's skillful to overcome such thoughts.
However, Buddhism doesn't really teach us to forcibly suppress all our cravings. If you are craving to read about history, or craving to eat a slice of cheesecake, go right ahead. The Buddha taught us to overcome craving not through forcible suppression (unless it leads to bad kamma), but through uprooting ignorance, by gaining wisdom and insight.
This answer which introduces the old South Indian monkey trap, explains that to uproot craving, one must first uproot ignorance. However, the cause of the arising of suffering is still the arising of craving.
You can have interest (Chanda) without craving.
It is craving one should abandon. More particularly your reaction to different feeling (pleasant, unpleasant, neutral) with unwholesome mental states (craving, aversion, ignorance). See: Pahāna Sutta.
If you like reading do so which delight or aversion to what you read.
Examine the intention/motive behind one's interest to see whether it's wholesome or not, whether it benefits oneself and others, whether it helps alleviate suffering, increase one's virtues, and the cultivation of meditation and wisdom, etc. Regarding craving vs wholesome desire, see the park analogy at SN 51.15
If so, how do we approach so many activities in daily life, that rely on interest?
Interests skew awareness--an interest in following Instagram influencers easily leads to craving Photoshop delusions.
Interests lead to biases. Interests lead to favorites. And that leads to prejudices:
Making decisions prejudiced by favoritism, hostility, stupidity, and cowardice. AN4.19
Relinquishing favorites, one approaches activities in daily life with equanimity:
They live without wishes in the present life, extinguished, cooled, experiencing bliss, having become holy in themselves. MN51
Consider reading. It is natural to subscribe to news feeds according to interest. When doing so, simply subscribe to news feeds that collectively represent opposing views of the topic of interest. This provides a basis for practicing equanimity.
