'unabated interest' is correct and usable in written English.
You can use it to describe an ongoing or increasing level of enthusiasm for something, or sustained attention over a period of time. For example: The professor's unabated interest in his research project over the past two decades has resulted in many important discoveries.
Neither a book nor a film, it was a play, "Harry Potter and the Cursed Child". But whatever the medium, the Potter saga continued with unabated interest: fans dressed in Hogwarts costumes, curiosity about the fate of long-beloved characters and the allure of magic.
With an unabated interest in the fate of Russian oligarchs in general and Mikhail Khodorkovsky in particular, the channel secured a "lively and emotional interview with a man [i.e. Nevzlin] who met his closest friend [Khodorkovsky's] after ten years".
If your cat shows an unabated interest in your computing equipment and cords, besides cleaning the surfaces (which might be sufficient if she hates the smell of the cleaning solutions), try a cat repellent spray.
Interest continues unabated in catalysis by gold.
The regime censors soccer broadcasts, even inserting stock crowd footage to prevent unseemly images, but interest is unabated.
Interest continues unabated, as witnessed by the following publications from the period 2004 2006 alone: Hodes (2004), Cook (2005), Tennant (2005), Bonnay and Simmenauer (2005), Chapter 5 of Priest (2006) and Wansing (2006).
Gold catalysts, both homogeneous and heterogeneous, have seen a meteoric rise in importance in the last three decades, and interest continues unabated.
The law is designed to ensure that Mountain Top Removal Mining (MTR) continues unabated and the energy interests (especially coal) continue with business as usual.
Moreover, stocks that are traditionally sensitive to the economy, like Caterpillar and Goodyear, were trading as if a recession were imminent, even though virtually all the economic numbers show that the boom continues unabated despite four rounds of interest-rate hikes by the Federal Reserve.
Interest in Aristotle continued unabated throughout the renaissance in the form of Renaissance Aristotelianism.
Interest in Wave continued unabated.
