AES-NI won't be a requirement for ARM CPUs - Netgate sells first-party ARM-based pfSense appliances that have non-AES-NI hardware crypto acceleration that they've confirmed wouldn't be affected by the AES-NI requirement. Not sure how that applies to third-party ARM systems.
The SG-1100 is based on the v7 espresso.bin board. a 2G version of that is $99 by the time you have case, heat-sink, eMMC and power supply. We sell them for $159.
A 2G RPi 4 with case, heatsink, and power supply is $76.30. You have WiFi, but no second (or third0 Ethernet.
Also, someone has to pay the developers, right?