For score maximization, you do want to have at least 3 total revolving lines of credit, with 1 reporting a small balance and others reporting a zero balance. Beyond that, more CCs don’t help TOO much (more accounts IS always better, if only slighty, &; over time getting more cards early on helps AAoA later down the line, but you’re running up against a diminishing returns curve. For non-CC lines of credit, getting more CCs beyond 3 may or may not help at all)
You’ll find a lot of ppl here really maximizing their scores by getting every card they can get their hands on and then making sure they use each card at least once every few months, so that their AAoA never significantly drops, even if they add 2-3 new cards at once, but, tbh, if you get a few revolving lines and pay as agreed for about 10 years, you’ll never need to worry about demonstrating credit worthiness to a CC issuer again (totally different story when it comes to getting other types of credit, but again, additional CCs won’t help a mortgage score.)
Furthermore, 1 derogatory is enough to tank your score, even if you have 30 CCs.
