Hi, so Singtel TV Go and Singtel Cast can work on any Android box (both TV and mobile OS) provided it is not rooted?
The generic Android boxes I have all come rooted and there are no ways to hide the root. So I do not have experiences with non-rooted box or rooted box which can hide the root. In fact if you install those root manager apps, the boxes I have will brick and you have to reflash the firmware.
That being said there are some Android TV boxes which are not rooted.
Mecool KM8 is one such box which claims to be Google Certified. It runs Android TV OS and does support Chromecast but not Netflix. I do not quite trust this one so I do not normally mention it. From various website it seems to me it is true that this box may have gone through some types of Google certification and has the Google Widevine L1 DRM for YouTube 4K but the firmware is buggy and it is not the same as Mi Box S which is fully certified by Google and Netflix.
Mecool KM9 uses latest S905X2 and runs unofficial Android TV OS which does not support Chromecast.
Both are running Android TV OS and not rooted. So you can not install Starhub TV Go and Toggle. But you might be able to install SingTel TV Go and SingTel Cast. YMMV.
Mecool has another two popular Android TV OS device, M8S Pro L S912 based mid-end box and M8S Pro W S905W based low end box. I believe both are rooted and both do not support Chromecast.
There are reports that M8S Pro L may run Netflix up to 1080p but there are also reports that it does not work. I think it is better just to consider Netflix HD as not working on this types of non-Netflix-Certified device as Netflix is actively enforcing copyright protection against VPN and non-certified device.