IIRC, Congress could hold a Constitutional Convention, present the arguments for & against an amendment and vote. If it passes by a wide enough margin, it can be signed into law. If SCOTUS strikes that down, it's probably dead.
I'm not sure I follow. It is true that the constitution can be amended, but once an amendment is in place the Supreme Court can't strike it down substantively (i.e. it can't rule that the constitution itself is unconstitutional). I believe that at least in theory the Supreme Court could rule on a procedural issue related to how an amendment was ratified, but I'm not aware of that ever happening.
Nevertheless, there is a huge difference between ruling on a constitutional issue vs interpreting a statute. To the extent my wording ("forever") overstated it, I will defer to the wording ("virtually final") on the Supreme Court website:
>>>When the Supreme Court rules on a constitutional issue, that judgment is virtually final; its decisions can be altered only by the rarely used procedure of constitutional amendment or by a new ruling of the Court. However, when the Court interprets a statute, new legislative action can be taken.<<<
https://www.supremecourt.gov/about/constitutional.aspx
The link below has a pretty decent summary of what congress can do if it disagrees with court decisions. According to this, there have been a total of five constitutional amendments that were at least in part in response to a court decision:
>>>Constitutional Decisions. Constitutional decisions by the courts limiting legislative powers are reversible, strictly speaking, only through amending the Constitution, a difficult and time-consuming process. Yet, that result has been achieved in the eleventh amendment,
7the first sentence of the fourteenth amendment, the sixteenth amendment, the nineteenth amendment, and the twenty-sixth amendment.
11 However, the usual result of efforts to overturn constitutional decisions by amending the Constitution has been failure. One need only think of recent movements, such as the drive to amend the Constitution to authorize legislation that would penalize desecration of the United States flag, in response to
Texas v. Johnson, 491 U.S. 397 (1989), and
United States v. Eichman, 496 U.S. 310 (1990). Earlier initiatives dealt with school prayer, legislative apportionment, and abortion. Only sustained and energetic work in Congress and in the States, complemented with vigorous public support, is capable of changing the Constitution.<<<
