Developers apparently cannot leverage the full capabilities of the 2021 Apple iPad Pro models powered by the M1 SoC. The new iPads come in 8 GB and 16 GB RAM options, but developers can leverage a maximum of only up to 5 GB limiting the potential of their apps even though the iPadOS itself can access the entire unified memory. It is possible that the upcoming iPadOS 15 may overcome this limitation.
https://www.notebookcheck.net/Fancy-the-2021-M1-iPad-Pro-with-8-GB-or-16-GB-RAM-Current-iPadOS-limits-potential-by-allowing-just-5-GB-memory-for-third-party-apps.541367.0.html