That's a lovely duvet. The issue is one of scale mainly, and shape. Both patterns are too close in scale. I think you're on the right track with stripes. Why not something more simple like this one also at Ballard?:

https://www.ballarddesigns.com/embroidered-square-trellis-panels---set-of-2/rugs-drapery/drapery/indoor-drapery/461314?uniqueId=461314&isNewProduct=false&newItemBadge=false&hideNewTagFromPLP=false?&defattrib=Color&defattribvalue=SAG

With the nice artwork and duvet, I would keep the window treatment simple with just a touch of color like using edging only. Here are a couple examples. Found these on the Etsy website.

Maybe take a cue from the bag hanging on the bed. Go to opposite side of the color wheel. Solid drapes in light pink could be interesting.

When I first read this post I remembered a scene from the movie "American Beauty". The wife, played by Annette Bening, was dressed to the nines and digging in a flowerbed. The wooden handle on her garden trowel was perfectly matched with the wood in her high heels.

I like @bearbev 's Etsy find a lot. It relates well to your head and foot board, coordinates with the duvet, but is different enough so as not to make the room too busy.

Either the patterned one or the plain with edging would work, it's your choice, no right or wrong. Bev's photo looks very pretty.

You don't care for it so keep looking. Perhaps you want more flowers less leaves? As far as the 'cheap' looking queries, more panels will give you a richer look.

Too busy on that wall already so try something plain in either just white or a green from the bedding . I do not like those drapes with the bedding .

How do you want room to feel?

Neutral drapes

Floral

Green

I agree--what do YOU want the feel to be? There's a very real fear of "busy-ness" on this site. Many Houzzers feel that any more than one pattern in a space is too busy. I happen to love mixing patterns so my tolerance for busy is way higher than some. It's really up to you. Just don't let your fear of pattern devolve into a room devoid of any interest.

Thank you

Also, I disagree with whoever said that the scale of the patterns is too similar. The curtains are a stripe and the duvet is a flowing floral. Totally different types of patterns. Scale matters with similar patterns--you really can't compare scale across dissimilar patterns.

If you truly do not care for the stripe curtains, then find something else. But don't discount them because of faulty reasoning.

To clarify, scale refers to size in this case, not type of pattern such as stripes, dots, florals, abstract, etc. (Scale, of course, as an old word with an interesting etymology, has many definitions:) Being English, I am used to mixing of fabrics/textiles in a multitude of ways. A good article to see is: https://www.homesandgardens.com/advice/how-to-mix-patterns-in-a-room. 

Another useful reference might be, Bunny Williams (Ballard Designs), an English-influenced American designer: https://www.ballarddesigns.com/howtodecorate/bunny/

That pattern would work fine, but a question is, what is in the rest of the room in terms of wood finishes and metals, which have a”color”, plus do you have a fave accent color you want to bring in. And I’m not worried about “ busy-ness” in Abstact— it’s what YOU want in the room. I like pattern mixing and sort of English cottage decor. Bedrooms sometimes need to be calmer, but that’s up to you. Plus I switch quilts throughout the seasons and like some contrasting in pillow shams of I get bored. Another thing is, your drapes will be closed a lot and will cover a lot of wall then, plus good full drapes will cover wall when open. So that might affect your choice, not because that pattern is too busy alone but might be too much with your window size.
You might scroll through a bunch of fully decorated bedrooms in your cokes, & see if you’re more drawn to calmer looks, pattern mix, walls of patterned drapes.

Love Maureen suggestion with the neutral drapes in first photo

Yes I know that scale refers to size of the pattern. The floral in question is a fairly large scale, and there's no problem mixing it with a large scale stripe, check, paisley, etc. The problem could arise if you mixed it with another large scale floral, which could work, but not everyone can pull that off. You could however easily mix it with a small scale floral or miniprint.

Maybe you do not love the Ballard quite enough? Ballard isn't the only place for a duvet cover, nd a duvet cover is just ONE piece a well made bed..

Below?

Pottery Barn.........

What I see below? The beginning. A nice bed, a little nature with the rattan trunk

The pictures on either side of bed? Feel too heavy, forced into their paces, and the dark frames a bit at odds with the summery bamboo. A second smaller night stand and a pair of lamps would be plenty. and pretty!

Do the windows NEED a pattern in this sort of light and airy feel? No, they really don't: )

Always begin with something you really love. Are the two pictures driving the choice? Or something else?: ) Nothing to lose sleep over......., right? Nothing feels airier than crisp white linen curtains over a natural woven wood shade..