I know of no Protestant tradition that says “everything must” be in the Bible - that’s not what Sola Scripture means. Further, the Trinity is clearly taught by scripture and scripture also records the deaths of the Apostles Judas and James.
The word Trinity isn’t in the Bible, and plenty of your fellow Protestants don’t believe in the Trinity. The Bible also doesn’t specify that the Trinity is one God in three persons. You have to go to Catholic teaching for that truth. Heck you have to go to the Church for the Canon of the Bible, and to the teaching of the Church that the Canon of the Bible is closed and that the books are infallible in matters of faith and morals.
This thread started off as the reasons to have a crucifix in your house (which some Protestants such as Lutherans and Anglicans have) and it was turned into an anti-Catholic everything thread. That says more about the posters than the Holy Catholic Church.