I would like to suggest that balenaOS or balenaCloud be made to serialize its operations on older devices. (I.e. RPi Zero W and B+ v1.2) One thing that kills my progress almost every time I make any kind of update, is that the application containers all stop, download and restart at the same time. On a device with a single-core CPU and poor storage performance, this is a disaster. The amount of device contention pushes everything way past reasonable timeouts and things just crumble and fail, and grind to a stop. The device never recovers from this. If these operations were serialized, so that only one image is being downloaded at a time, and only one service is being restarted at a time, and whatever other operations were queued up, things would go a lot smoother when updates are made. And it would take less time to make changes by eliminating a high level of device contention and context switching.
The devices handle the applications without any problem if I can get them past the issue of redeploying everything all at once every time I make an update.