What is the best device for btc mining . also profitable
The Bitmain Antminer S9. It's called an asic miner. It mines sha256.
You can also build a gpu rig with 1070, 1080ti's RX580's and run Nicehash.
Mining bitcoin is not very easy and how it looks is really different in reality. For mining bitcoin a person should need to be pro active and always connected to bitcoin because you will need to have latest knowledge about bitcoin to have a good next step all in know is that bitcoin mining is really good and give a person a lot of profit.