My conference paper got accepted. I was told I have an extra page for the camera-ready version. And my method is built upon an existing method. Now I realize that, in the existing method, there might be one key component that could tackle the proposed problem in my paper. Removing this component might not only influence the performance of the existing method but also my method. However, I skipped this detail in the previous version of the paper as I think this is not my main contribution and the space is limited. And also if I put the description of this component on the paper, I thought the reviewers might focus too much on this component instead of my own contributions. Should I add the description of this component into the new version given I now have enough space?
Usually not, but as Buffy said, ask. I don't know your field, either, so this may be specific to my own. However, accepted papers are almost never modified after they are peer reviewed, since even a "minor" change will need to be reviewed again. Think of what it might mean if a mathematical proof were accepted, then slightly modified but those modifications introduced an error. Without thorough review an erroneous paper would be published.
In many conferences I've been to the answer to that has been to address it at the podium, not the paper. Papers are written sometimes months before the conference, so it is accepted that more work will be done. Use your talk to introduce those changes, and then turn the work into another article.