Adding Offscreen Rendering for High-Resolution Screenshots

I understand that the scale factor has not been functioning properly for some time, and in order to obtain high-resolution screenshots, it appears that offscreen rendering is currently the only option. Is it possible to add offscreen rendering as a feature to replace scale factor?

Yes, it would be possible but it would require some effort. People who want to see this happen sooner should vote for this feature request. See this post for the current workaround.