blockchain.com mentioned unknown for block 649390
Whereas btc.bitaps.com shows "Huobi" as mining pool for the same block: https://btc.bitaps.com/649390
Coinbase text: =h_HZ/HuoBi/mmwta@F,Cn3ǐIK(
There are no exchanges or services which sell testnet which I know of.
Instead of purchasing directly, mining hardware can be borrowed or rented to directly mine testnet coins. CPU mining is no longer a real possibility for generating over 1 tBTC.
The steps for mining testnet coins would be the following.
Setup Bitcoin testnet full node
Setup pool interface ...