Firstly, the heading of the topic says
"how to choose crypto exchange?" But, the article speaks only about Non-custodial exchanges.
OP great article with detailed explanation.
There are many crypto exchanges where you can buy cryptocurrencies. It is important to choose the right exchange based on your requirements and what's best for you. Some of the factors to consider are:
Choose the exchange that supports buying of coins with fiat
Number of coin pairs available on an exchange
Ease of use: It should be easy to buy/sell cryptos without any confusions.
I kind of have a different though on this. If you see at Bitmex it has limited coins available, only XBT deposit and withdrawal, There is no buying or selling still the exchange has a crowd of people using it.
I think it is also the extra features that a exchange provides that makes the exchange stand out of the crowd and gets its customers.
Other features like Security and support yes, they do matter.