Apple seems to suggest it's only available on M-series. I think if A-series could do it, Apple would have implemented it by now, especially on the lower-end iPads.
When virtual memory was introduced with iPadOS 16 Craig Federighi stated that the feature was limited to M1 iPads for performance reasons. The SSDs on M-series iPads are quite literally 10x faster than on the A-series iPads, even A12X/Z series iPads (that's more due to the SSD chips used than the A chip itself). Since iOS/iPadOS currently did not leverage any kind of swap and as a result had a certain responsiveness even on limited hardware Apple reasoned (rightly or wrongly) that introducing relatively slow memory swapping to flash storage would make for a worse user experience.
You can call BS on Apple's explanation (the SSDs used in A-series iPads and iPhones are still faster than spinning hard drives and SSDs from 10 years ago), but Apple explicitly stated swapping was restricted to M series iPads specifically for performance reasons and not technical reasons.
Plus Apple has a vested interest in selling you a more expensive iPad that can utilize more RAM.