What is the simplest way to render an image of an obj exported from Tinkercad?
For your purposes, consider that Meshmixer (free) can open .OBJ files and display them in any position you desire.

I use Meshmixer quite a bit for model editing, but have not used it for .OBJ files with textures. I searched my drive and found quite a few .OBJ files, but was not able to present or add textures, due to my own ignorance, I'm sure.

I found a useful link to a support page on the 'net which indicates that there has to be a texture file as well as a definition file (.MTL) in order to display the textures in Meshmixer. Using that reference, I was able to add a randomly selected .PNG file and apply the texture to a test model.

If your creations do not include those support files, this may not be a good answer. There's little to lose, however, as the program is free and you may find use for it in the future, or you may find that it works as you require.