Analysis for difference in variances between group?

I have data for 100 different biomarkers. Each biomarker has data for 4 groups (A,B,C,D) with ~2000 observations in each group.

I've read a lot about ANOVA but I'm not looking for a difference in means, only a difference in variances between the 4 groups, for each biomarker. I know there is the Levene and Bartlett test for this but was wondering if there may be a more sophisticated analysis? Especially for the large number of biomarkers.

I've been looking at multivariate methods, such as Mahalanobis distance but can't figure out how exactly they would work for my data. I would really appreciate any suggestions!