A number of applications in the Patch My PC catalog offer ARM architecture support and this seems to be gaining popularity. A couple examples I've noticed thus far are Cisco AnyConnect Secure Mobility Client, Sysmon just released ARM support this week, and Zscaler is slated to release an ARM version with their next major release.
This could be accomplished either in the existing deployment type code where the architecture is detected and the appropriate source file is executed or through a second deployment type with Requirements set to all the Windows ARM OS versions.
Just adding some additional information as it seems vendors will implement arm64 support in different ways. Some applications seem to have separate ARM installers, while others include support in a single exe/msi. For those that have separate installers, I suspect it would be easier to have an additional application/update checkbox, similar to how many applications currently allow you to select either 32bit or 64bit versions. For the ones that include support in a single installer, detection method script may need to be adjusted slightly(still trying to test this) and the requirements on the deployment type will need to include the Windows ARM editions supported.
Examples I've come across thus far....
Cisco AnyConnect Secure Mobility Client - separate arm64 installer
Sysmon - separate arm64 installer
VS Code - separare arm64 installer
Zscaler - included in single installer BUT currently only supported on 32bit. Version 4.2 is supposed to include 64bit support
These aren't handled by PMPC but just additional examples of applications that support both versions in a single installer:
ConfigMgr Client
ConfigMgr Console