That's a beautiful panel.
I had a similar problem recently. I just pretended like it was correct and cut a 1/4" seam allowance all the way around it and I sewed on borders that it wouldn't be obvious. You could make some wonky stars and use different block sizes of the angels and put them inbetween the wonky stars.
Don't stress, only in a quilt show will they take a tape measure to the quilts. And after it's washed, no one will be able to tell anyway.
If it was me and that was my panel, I would just use that striped fabric and make a mitered border around it like a frame and make it a wall hanging. It's an absolutely gorgeous panel.