There are so many options that are portable. Midwest makes a collapsible cage that is available through Chewy for $110.
https://www.chewy.com/midwest-collapsib ... n/dp/45740. This come on wheels and doesn't appear to be too large, but large enough. If your deck gets a lot of sun, you can place something on top to give the playpen (they call it) shade. The dimensions are 36 x 23.5 x 50.5 inches high. This would also allow your kitties get up higher. If you just Google "portable cat enclosure," you will find many options at all sort of prices.
It's wonderful you want to keep your babies safe. A 22 foot jump would probably result in broken bones (my friend who has a cat sanctuary is now caring for a cat that jumped off the roof of a house and broker its leg).