2GB of RAM [in the best CuBox] is not great, but doesn't stop you from building kerrnels. In this case, the CPU is going to be the real bottleneck.
Of course it's not SBSA, since this is an embedded 32 bit SoC. Almost no 64 bit machines are SBSA either (most big server chips claim compliance but are lacking somewhat), but generally nobody actually cares.
HoneyComb LX2K is probably what you want if you can spare the change and wait for the last missing bug fixes.
The RK3399 chip is probably a good compromise between performance and cost, there are various boards with 4GB of RAM and an m.2 slot for storage, around $100.
Why does have to be like this? All I wanted was to make usbmon work on ARM.
The assertion that nobody cares about SBSA is rather interesting. Obviously, nobody in the embedded area does. They just fork Linux, clone a bootloader, flash it and ship, and then your refrigerator sends spam and your TV is used to attack your printer, while they move on the next IoT product. But I do care. I want to download Fedora and run it, like I can on x86. Is that too much to ask?
The HoneyComb LX2K is made by the same company as CuBox, but the naked board costs $750.