Why are getNativeDataPropertyPure, NativeSetProperty etc so expensive?

Hi,

I am currently benchmarking an in-house application based on the RAP framework.
Currently navigating from one data set to the next one means 2s
processing on the client side with firefox and I would like to improve
this.

However, the profile obtained with firefox profiler isn’t that
conclusive to me: https://perfht.ml/2ZslmJq
The hottest function seem to be some accessor functions
(getNativeDataPropertyPure, NativeSetProperty, AtomizeString,
GetNativeDataPropertyByValuePure).
Are those DOM accessor functions? Are they actually “summing up” the
time spent inside some native DOM code?

What would be the next steps to understand what is going on there?

Thanks and best regards, Clemens