Perplexity is great for research and information gathering but processing data and giving a result is a separate thing. Perplexity do sometimes give better answers even when solving questions but in my experience chatgpt is still better. Chatgpt processes date and generate results more accurately. Claude, what I have seen, gives good descriptive results but fails to analyse and process so not good for technical answers. Aslo side note, never consider gemini an option, it never was and never will be. Guthub, I've not used however some of my friends told that it's good only for supporting while coding other than that not recommended, not for answers and not for non-coding related questions.
You can also try microsoft copilot, it's a risky one but sometimes it gives correct answers that gpt even though it's just a python script over the gpt model
Tl;Dr ChatGPT is the best, Microsoft co-pilot can be considered as a second advisor.