"filter" similar to a DC filter
 

Hello! I apologize if I am not writing in the appropriate section.
I have such a situation. The synthesizer (Serum) has the same frequency spectrum as in the left image, but I need to do it as in the right one (approximately). This image was obtained by chance, using the "Effector FX module" tool, it is inconsistent, difficult to adjust, and almost by accident. I'm looking for a "filter" similar to a DC filter in electronics, which smooths the sawtooth signal to a constant, filling the gaps between the peaks, only in the digital version, so that I can smooth out the sections between harmonics from a digital synthesizer plug-in, at least with minimal settings and moderate constant effect. Can you remember something like that?
https://i.imgur.com/Oexkntn.png

Something like this?

https://www.sweetwater.com/store/det...filter-plug-in

Search for "electronic DC filter plugin" and you'll find plenty of options.