Are DEXs legal?

I'm curious to know, are decentralized exchanges, also known as DEXs, considered legal in the realm of cryptocurrency and finance? I understand that traditional exchanges often face regulatory scrutiny, but how does the legal landscape differ for DEXs? Are there any specific jurisdictions where DEXs are explicitly allowed or disallowed? Furthermore, are there any potential legal risks or considerations that individuals and businesses should be aware of when utilizing DEXs for their transactions?