Security on steam link or equivalent

[BabyColor]

Hi, I'm planning to get steam link or turn some old windows pc into steam stream box and attach it to the living room tv. But i am concerned about my account's security, since it is on a computer that i can't always supervised, and unchecked the auto login on the steam program would make the need for a keyboard to login and it would be a hassle, which is kinda defeat some of the purpose of steam streaming itself. Now the question is? It posible to set a machine yhat can just do streaming, and no. More (no modifying profile, and most importantly, no modifying the library itself like buy or remove)
Well i know it will be placed on my living room, which usually no one beside my family able to access, but i still, sometimes we would have a guest, and, you know, well i kinda paranoid when concerned about security of online accoubt.

[PizzaBoy]

Use Family View, and disable everything except the game library.
For the steam link, go to Settings -> Brodcast: Friends can request to watch my games
Settings -> In Home Streaming: Set Steam Link Pin Code.
Family sharing is an option for security too.

[BabyColor]

Ooo neat, thank you