There's no "best crypto exchange" there's the best one for what you're actually doing

Every tier list thread here eventually devolves into tribal warfare reality is simpler.

If you're in the US and want simple fiat on/off ramps: Coinbase or Kraken, done.

If you're trading derivatives or alts outside the US and care about execution: Bybit or Bitmex, pick based on which UI you hate less.

If you just want to accumulate BTC and move it to cold storage: honestly any of them, you're not staying long enough for it to matter.

Stop asking which exchange is best ask what you're trying to do.