Thanks, it is good to know that this can be done by converting it to a continuous signal!
Alternatively, I found out that when you have equally spaced (discrete) values (e,g, daily averages coming from using signal from condition using a periodic condition) that you can easily code the finite difference scheme yourself allowing to go broader than only the adject points or to use scheme of higher accuaracy order, e.g.,
($signal - $signal.move(+7d))/(7d)
This may be a little bit less noisy although differentiation inherently amplifies the noise 🙂. So removing outliers and filtering the original signal is surely advisable.