Is dYdX not available in USA?

I've been hearing a lot about dYdX, its innovative trading platform and its decentralized exchange functionality. However, there's some confusion in the crypto community about whether dYdX is accessible to traders in the United States. Could you please clarify whether dYdX is indeed unavailable in the USA? If so, what are the regulatory reasons behind this decision? And for those in the US looking for a similar platform, are there any viable alternatives that offer similar features and trading options? Your insights into this matter would be greatly appreciated.