Buying bitcoin is always risk, you can make quick profit or quick loss.
so, you need to research and carefully invest in it.
Buying or investing in bitcoin is not that risky because you can still make profit without having a good research because if you buy bitcoin now and keep it for a long time then you can easily earn money and for long term investment, it doesn't need a good research because, research is good for short term and for people who wants long term doesn't need that and they just need guts to hold it for long and also patience.
I wouldn't say that you can invest in Bitcoin without research AND have it not be risky. There have been many, many, many points in the past where Bitcoin has dropped in value for a very long period of time, and it is not impossible for it to happen again. Unlikely, but possible. You always need to play the market in order for something like that to be remotely viable.
You also have to keep an eye on global trends, but that's a comment for another day.
It requires knowledge because the word of investing is very risky, we've seen bitcoin grows substantially last year and if we
only follow the trend we can make easy money. But, we also need to be updated as we do not know what will happen in the future.