Instead of doing the crossword directly in Screenshot, you could save it to another app and do the crossword there. Freeform would probably work best. You can resize the puzzle there, and even keep multiple puzzles on the same board. A record of you past victories, if you will.
Notes will also work, if not as flexible in how the puzzle is presented.
Also, the tool background is a bit better in the iPadOS 27 Developer Beta. Along with the Liquid Glass adjustments possible you might find it more palatable (pun intended). Something to lookk forward to when you update.