The case may certainly be made that Supreme Court justices are ideological. But first, let's examine what ideological means. Oxford Languages defines the term as "relating to a system of ideas and ideals, especially concerning economic or political theory and policy."
Using that definition, are Supreme Court justices ideological? As human beings, they are entitled to their own ideals and political leanings as much as any other citizen of the United States. The real question, then, is whether those preferences affect their rulings.
There is some evidence that indicates that a Supreme Court justice's political leanings do influence their interpretation of the Constitution. This becomes even more visible when looking at those instances when a judge casts the deciding vote in a particular case. I'm linking an article below that examined 8,500 cases since World War II and examined trends and patterns in the swing votes over time. According to this study, when a justice casts the deciding vote, "his or her personal beliefs suddenly matter far more."
While the Supreme Court was intentionally designed to be shielded from the influences of public opinion, recent cases seem to prove a strong correlation between public opinion and the way the Court as a whole rules. When conservative Brett Kavanaugh was appointed, the Court's "ideological median" shifted a bit to the right. We could therefore assume that its rulings would reflect a more conservative political interpretation of the Constitution.
Yet studies found that the Court's rulings were "exactly in line with public opinion," which actually leaned to the left (see linked article below). In cases involving LGBTQ+ rights, abortion access, and presidential powers, "every major case" reflected the beliefs of the public majority.
Supreme Court justices are certainly mindful of maintaining a sense of relevancy. In order to avoid becoming stagnant, they are almost compelled to examine the way laws and policies reflect the views of the populace. Justices are also not islands of opinion and must therefore interact with various special interest groups, politicians, officials, and ordinary citizens. These interactions have the potential to shape the way a justice interprets the Constitution in various cases.