I want to look into dexes and I was wondering what is it that you would personally look for in a dex to see if it is good?
Check if the decentralized exchange have terms of service. If they have, you need to read it. From reading it, you will be able to know how truly decentralized exchange they are.
But if I will advice you, you can go for decentralized exchanges like Bisq. Other decentralized exchanges are not decentralized entirely but somehow centralized.
If you want some other decentralized exchanges, read the link that Coyster gave above:
https://kycnot.me/But the link is more about no KYC exchanges. The highest ranked ones are decentralized, especially Bisq which is the best among decentralized exchanges.
In a decentralized exchange, you should try and know the coins they support and the fiat they also support.
You should try and know about their trading volume also.