I would like to backtest my strategy. Where should I start?

Hello everyone, I would like to ask for some guidance and help. My goal is to gather information about the S&P 500 index across various timeframes, all the way down to 1-minute charts, going back up to 20 years (though if that’s too resource-intensive, 1-5 years would be enough to test my ideas initially). For example, I want to check during a specific intraday period whether an RSI-EMA 21 crossover occurred, what the RSI values were on different timeframes at those moments, and whether the price reached a specific Fibonacci target within the next hour after the crossover. I aim to create statistics and perform backtesting on these. So far, I’ve only coded in Pine Script and use Claude 3.5 and GPT-4 to help me. I’m a quick learner but have no experience with Python. However, I believe I can code what I need with AI assistance. I’m looking for a solution that will allow me to do all this. I’ve read that I could use APIs and analyze data with Python, which seems like the best option. But what application should I download to achieve this? What is the most effective yet beginner-friendly option? I’ve also heard about QuantConnect, though I don’t fully understand it. It seems to offer possibilities for this purpose. Perhaps it’s simpler and better suited for me? Since I want to work on this long-term, I think a Python-based custom solution might be better. For example, is this video a good resource for my case? [Algorithmic Trading Using Python - Full Course](https://www.youtube.com/watch?v=xfzGZB4HhEE&t=5844s) Since I don’t know much about the other options, I’m unsure if this is the best choice for me. Thank you!