Of cause I DID a research before refering to forum.
I doubt that you have found enough information to understand how it works. POSITION STICKY depends on the parent container, from its height and overflow properties. In general, in most cases POSITION STICKY is not applicable. The deeper the DOM structure is the element, the harder it is to make it work in this mode. This may require the breaking of the global overflow properties for parent elements, up to Body. Too much price, in order to make it work. Use old good JavaScript solutions.
Well, as for the working code for Sp Pb. Add the following code to what you already have and you will understand how it works. And what can be the area of its application.
.sppb-addon.sppb-addon-raw-html .sppb-addon-content {
height: 500px;
overflow: auto;
}