I’ll take your word for it.The 6GiB iPad Pros do close apps fairly often under heavy use compared to the M1 iPads with 8GiB so in that regard there is a noticeable difference for me.
I know my use isn’t particularly heavy (mostly note-taking, browsing the web, and the odd edit in affinity photo) and whenever I play games I usually close them manually when I’m done 😆