@Lily Sun, Thanks for posting in Q&A. For Android, the supported system in Intune is Android 8.0 and later (including Samsung KNOX Standard 3.0 and higher.
https://learn.microsoft.com/en-us/mem/intune/fundamentals/supported-devices-browsers
For Android enrollment, there are many enrollment methods. Based on my researching, the Android smart TVs is not in Android Enterprise supported list. Ao it can't enroll with any method of Android Enterprise.
https://androidenterprisepartners.withgoogle.com/devices#!?search=android%20smart%20TV
Note: Non-Microsoft link, just for the reference.
Based on my knowledge, these devices generally run a non-GMS based version of Android and have little to no manageability built in.
The only method, I can think is Android device administrator. But this method will be ending support on August 30, 202
Hope the above information can help.
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