I see BSC as the closest "competitor" to Ethereum once they transitioned to POS while Polkadot, Cardano and Solana not too far behind BSC. I have no idea if the other chains on the list have huge followings to even compete.
What's up with Binance Chain & Binance Smart Chain

Isn't that the native chain? Tokens built there are called BEP-2. They have no smart contract capability and so comes BSC.