@Armin
if you need just something such small, you may find nanopi or orange pi boards. Some small models are pretty cheap (<10$) and well supported by armbian. Tv boxes have no exposed GPIOs, which can instead be very useful for domotic applications.
For example, I have an old Orange PI One (Allwinner H3) which has ethernet, 1 USB port, 512mb of ram and some exposed GPIO. I paid less than 10$ some year ago. I guess now you can get something similar with wifi too at the same price.
