There is no best exchange in my opinion, whether they're a DEX or a CEX they will always possess a flaw that can hinder them from being called "The Best Exchange" - instead people should search for an exchange that fits their preference, list some qualities you're looking for in an exchange and start comparing, now If nothing checks all your boxes then you might need to choose which comes the closest, looking for the best exchange will only complicate things for you and you're probably going to take forever searching for it because It doesn't exist in the first place.
These people under your replies are just stating their preferences, they're not giving you the names of the best exchanges. I was also looking for an exchange to do my trades last year, and I was proud of myself to find a place that I prefer instead of what people recommended me and calling them "The Best Exchange", that's pure BS.
Then I started trading with this pair
https://trade.kucoin.com/ETH-BTC immediately, and yes I chose KuCoin out of all of the options I had, my trades aren't all good but part of it is my fault anyways and I am still having a decent experience with KuCoin's trading services which are obviously meeting most of my expectations.
My advice? YOUR INVESTMENTS, YOUR DECISIONS.