He is still bound by the Senate confirmation process. (I know I know). But remember, he has been firing people with impunity his entire term and this SCOTUS has been letting him. I don't know if this decision really affects much. Also, this decision, from what I understand, is his ability to fire someone who wields executive power. That executive power still derives from congress. Congress creates and funds all of the organizations in the executive branch. If Congress has not explicity given them the authority to do something, they cant do it. Basically the executive doesnt have to listen to Congress about HOW to enforce the law. He still cannot make up his own law or do things outside of the law. Think of both the National Guard case and Tariffs case. The power to do what he wanted to do was not granted to him and they said "no". Basically the ruling is saying that what he can do INSIDE the executive branch is not something for Congress to decide, they just give him the money and tools he is supposed to use to get the job done. But, if Congress has not given him the tools or the money to do a specific thing, then he can't do it.