But if you ask me I personally use KuCoin but I didn't face any issue. They have high withdraw fee and minimum deposit threshold just due to this I rarely use KuCoin.
I have a Kucoin account also and I can say they are one of the centralized exchanges that I trust. I once had a deposit issue so I contacted their customer support immediately. I didn't have to wait many hours to get a response and their reply was clear from my query.
Review sites like Trustpilot can't be reliable and sometimes the review are being made to destroy the reputation of a particular platform. It's better to check them yourself to see if the reviews are true or not.