It looks like you expected a study answering the question "Is 5G harmful or not" to which the authors have no pretense. Instead, they address a different topic:

It looks like you expected a study answering the question "Is 5G harmful or not" to which the authors have no pretense. Instead, they address a different topic: how to precisely assess the effects of the radiation on tissue. They present at least one conclusion: that the method of using gel for assessing it in other studies is not as precise as it had been thought, and that studies using it might underestimate the effect. The study is more for having a more precise base for further studies and discussion that could answer key questions and help to establish safer SAR levels for device manufacturers/policy makers.