My, that's really beautiful! I especially like how realistic the grasses and shrubs look in the the background. Did you use Painter to make this one ?(the clouds look just like oilpaint) Or parhaps another program? In any case you are clearly an accomplished painter! 🙂
On the matter wether it would be too busy to use as a background, I would say not necessarily. If you put you character on a seperate layer in the foreground, you can go on change and tweak things in both the character and backdrop to make them look seperate from eachother (but seeing how skilled you are, You probably knew that already). One thing that always worked for me is brushing on a very, very slight dust or mist haze (big, soft brush at very low opacity) in either very light blue or yellow (almost white) between the two layers. Or slightly blur the background towards the distance.
In any case I would finish the foreground (character) and put it on your background first. It is perhaps not even necessary at all to make any changes to your backdrop.