US has been massively abusing TWO and has blocked judge nominations so cases against it can't go forward https://www.scmp.com/week-asia/explained/article/3042511/us-has-crippled-wtos-appeal-court-what-does-mean-asia

China also published an interesting report on the subject, in particular:

The US poses the biggest challenge to the global trading system. Following “America First” policy, the US has refused to shoulder its due obligations under multilateral trading agreements, and withdrawn from international treaties and organizations, taking a heavy toll on the development and functioning of the global trading system. A WTO dispute settlement report has identified the US as the biggest rule-breaker, responsible for two-thirds of violations of WTO rules. The US also blocked the appointment of new judges in the WTO Appellate Body, leading to an impasse in the Appellate Body since December 2019.

https://www.mfa.gov.cn/eng/wjbxw/202206/t20220619_10706059.html