Instead of plain sashing, consider using different size long rectangular pieced units ... like a string of flying geese, or a string of 9 patch squares. It will retain the scrappyness and at the same time bond everything together as pieced units ... IOW a sampler quilt.
Start by laying out your largest squares in opposite corners in the overall size you want, then place the other squares you have, then "fill in the blanks" with more units. L shaped units work well in sampler quilts.
Here's a sample of what I am talking about.
https://ondrivethrough.com/awesome-q...ampler-quilts/