>>72477282ignoring design, the first thing you should be doing is retexturing the hair, VRoid hair looks like shit, ame-chan's hair texturing style works fine and it's simple enough to do, just keep it fairly flat colored with a nice looking highlight. Frankly a lot of the vtuber model will not be seen unless you do something that requires full body, so first and foremost I'd recommend getting some really attractive face. I think Vei has the best chuuba model I've seen so even if the design has nothing to do, the technical skill and detail level is something that you could set as a goal for what a good 3d chuuba model looks like
If I had time I'd make a quick guide to fancying up even the ugliest models because Vroids meshes look fine and with hanatools you can get decent arkit tracking, the texturing and Mtoon shading are the biggest problems of vroid models. Also use Warudo, it's better than vnyan so long as you can run it, includes bunch of fancy shit and nice pendulum stuff to emulate l2d models
I like the robot approach, but Vroid will suck at it so in all honesty go for the tattoo options. Obligatory you should learn blender, it's easy as fuck as even the smallest edits to your vroid can help a lot