Shocking stuff. I was also dumb enough to buy a cheap streaming device from China, but it was very slow and Tubi didn't work, probably because most of these devices haven't got the correct DRM firmware installed. It's best to stick to the known brands like Google, Nvidia, Apple, Amazon and Nokia.
I believe it was this one. I don't know if it was infected but it's best to stay away from these devices, because they are basically crap. I honestly don't understand why such devices are being sold in the first place. https://androidpctv.com/x96-x4-review/
They are very useful for watching your own content over a local network, e.g. with a hard drive or SSD attached to your router. They are also great for watching pirated content, not that I recommend doing so, or for emulation. For watching legal streaming services, it's best to buy one running Google's Android TV OS, with Widevine level 1 DRM. The TV boxes like the one you bought run the Android, which is you will find on phones and tablets, rather than Android TV. If a device has Widevine DRM, which one of the ones running Android TV usually do, you can stream content from legal streaming services in 1080p or higher resolution. The TV box also needs to be Netflix certified, if you want to watch Netflix is HD resolutions. On TV boxes running Android TV, the Play Store has a much smaller selections of apps, as it only includes one that can be navigating with the arrow keys on the remote, rather than needing a mouse, or some sort of mouse support on the remote.
OK, I see. And yes, for watching legal streaming it's pretty much pointless to use them. But they are also quite slow, even YouTube didn't work correctly.