Split Screen Not Working with Preview

I have a Macbook Pro Retina 13-inch, early 2015, currently running macOS Monterey 12.7.4. I am trying to view two preview windows using split screen/side-by-side view. I am able to split my screen with one of the preview windows and another program, but not the two preview windows (screenshot attached). I have 'displays have separate spaces' selected under mission control, which was the only solution I was seeing other people suggest for similar problems. Any idea why this is happening and happening with preview windows specifically?