The area of interest is between the section of Jest loading and when the tests themselves run. Look for the bar which has your test file at one of the upper levels.

From there, starting looking at some of the widest paths downwards. maybe 10 levels down you should have some bars that are still pretty wide (indicating a long time to process), that you wouldn't expect to be required to run the test.

With normal imports, the flame chart quickly narrows as each import quickly runs out of new files to import. With barrel files, each flame is quite wide, and stays that way down the flame as the imports keep identifying new files to import - often running out after having processed an entire library, or your entire application.