Trading for stable profits requires following a strategy. Why did I heavily invest in Tesla below 300, only for it to rise to 500, then fall back to around 430, and I still added more like an idiot?

I have shared trading tips multiple times.
Building a position at the bottom or during sideways movement is simply buying horizontally, averaging down, or buying during consolidation. Below 300 clearly aligns with the strategy.
When the market starts to move, the first buy is at an ideal price (below 300 is suitable), the second buy confirms the pattern, and the third buy breaks through the trend. Using weekly charts as a cycle, determine whether Tesla has a breakout pattern and confirm it yourself.
Some people say this is the top. You might be right. For a leading stock, as long as the company's business moat remains and the outlook is still positive, why would you think it’s the top? If you analyze the top seven US stocks with a technical perspective based on a US stock market crash mindset, Microsoft would have long since shifted away from selling CDs, Nvidia would be recycling copper, Tesla would be into used cars, and Buffett would have renamed himself Gaddafi.
Any giant among US market leaders, to confirm a top, there is only one way: if the company has issues, lacks continuous innovation, and cannot attract future growth, then the K-line will naturally reflect this in advance, like in recent years with Intel.
Tesla itself is a stock price that overlays expectations of new and existing businesses. Large fluctuations are normal.