Forensic science or criminology?

Is forensic science more interesting than criminology?

Have you attended any open days and listened to the subject talks for both courses?

nope

Then I suggest you do -- it's the best way to judge if you are going to find a course interesting or not. Read through all the modules on the course page on uni websites too.

Well one is an area of applied science while the other is a subdiscipline of sociology so this is a bit like asking "is chemistry more interesting than politics". In which case the answer is really "well depends on the individual...".
If your interest is in pursuing a career in forensic science I would strongly suggest doing a "basic science" degree in e.g. chemistry, biochemistry, biological sciences etc, rather than one of the many "CSI degrees" which are of debatable value. That way you'll have more options if you struggle to get into the field initially, as it's not really a growth area (in the run up to covid several of the major private contractors in the field were at risk of going bankrupt for example...).
Also bear in mind it's not a job in "interpreting evidence through science", it's a job in "conducting scientific analyses to an exacting standard to ensure they hold up in court" - your job as a forensic scientist is to do the labwork, not to interpret it (and if you did interpret it you could compromise the validity of the testing and evidence due to allegations of bias in how you handled it...). As I understand a lot of it is really just kind of basic lab tech type work with a different "application" of what you're working on, and does not pay especially well either anyway.
Bear in mind also that criminology is an academic field, a subdiscipline of sociology - it's not a degree in "criminal profiling" or any such thing (which has been widely debunked as a concept anyway), but a field that explores the social causes of offending and the barriers former offenders may face in re-entering society, as well as the ways in which offenders are sentenced under criminal law and different theories on how to manage offenders in a society. You might cover a lot of the same areas in a sociology degree as well for example.
Since both areas seem to get widely misunderstood (often based on popular media misrepresenting the areas) I think it's worth noting the above.