Hi!
I've been doing some of my backgrounds for PontisSaga (a webcomic I'll publish soon) in Blender.
For example Peerless Dad Webcomic has some great backgrounds which rely heavily on 3d renders(stylized).
But first of all I think it is crucial to get some experience in drawing Backgrounds without any help. Then you could learn a 3d software that fits your need, mine is Blender.
My process varies a lot but sometimes I draw a sketch where the perspective and the composition is already worked out. After that I bring it into Blender and add it as an background image so I can fit the things I build there to my sketch. The modeling can be done at this stage or beforehand. Then I bring it back into ClipStudioPaint to use it in my drawing.
If you have worked on it a bit more in your drawing software you can still bring it back to blender (via backgroundimage) and add some 3d objects.
Repeat.
It is noteworthy that Clipstudiopaint has an awesome perspective tool (perspective ruler), you can set up as many vanishing points as you need!
You can also import 3d Objects directly to it.
Blender 2.8 is easier to learn then ever but it takes some time to get comfortable using it.
Boxcutter and Hardops are some super usefull (paid) addons for Blender. Check it out!
If anyone is interested in my workflow it's a good idea to follow me on twitter via thesoulstinger.
Just ask me anything there!
Hope that helps!
The following image is still WIP and I used the explained workflow on it: