I find coingecko's ranking to be relatively objective and reliable at the present.
1 Binance
2 Kraken
3 Bitfinex
4 Gate.io
5 KuCoin
6 Bittrex
7 Poloniex
8 Coinbase Pro
in what world is kraken #2 and coinbase #8?
according to the BLX, kraken's BTC/EUR and BTC/USD markets
combined represent not even 70% of coinbase's BTC/USD market by volume.
gate.io at #4?

this list seems like an attempt to hype up some smaller exchanges by mixing them in among real, high volume exchanges. it doesn't look objective at all.
Not all accurate how come kucoin is in the top 5 morethan bittrex and poloniex. In my opinion this is only base in one day or weekly volume and volume can also be faked i remember bitforex do this fake volume last year to be in the top exchange.