It's quite difficult to pick up a good and reliable exchange but I'll try. To me, it's Changelly Pro. Can't tell you why. I just registered there and don't want to move on searching for another platform.
I still think you should create another big exchange trading account, don't put all your money in one exchange, it will be very risky.
We see a lot of scams or hacker attacks, so don't be subjective because any exchange could be hacked in the near future. You can check out a list of big scam exchanges and hacked issues in 2019 here:
https://currency.com/biggest-cryptocurrency-scams-of-2019Although Changelly Pro is a good exchange, you should also preserve your capital well.