It seems that the copilot they sell for office/windows is super nerfed and barely better than asking bing. I don't know why they have taken so much effort to make it useless other than it must start spouting political opinions or complaining about their own software otherwise. Github was OKish, but now its kinda crap compared to the cursor.sh tuned versions of AI. Even cursor is a little uneven, but at least it gives decent code on well documented systems/APIs. It is about 90% hallucination free when you ask it about any Windows or Linux interfaces. Claude still seems the best for code and ChatGPT for planning/designing. Claude will still more time rewriting and ripping out functional code randomly(even when you ask it not to in rules and on the prompt), so you have to watch what it does but it is still saves a ton of research and development time.
Keep your source files to a single task/class and no more than 2-300 lines. Use meta-programming to manage code.