Cryptocurrency trading is riskier, fluctuating but also more profitable, high risk = high profit.
Both of them are risky. No speculation based marketplace is risk free. If you are doing it then you are taking an inherent risk. Thats the price for the reward.
If you are new, I suggest you try forex first, especially learning about technical analysis that is suitable for your trading strategy. And then learn to read market trends, learn a fundamental analysis and sentiment analysis.
I would not suggest someone to go for this or that. Depends on what the person prefers and what they are more comfortable with. Someone may have been doing forex for sometime and find trading it easier. Its possible to diversify and learn about another one like crypto but this is tough and practically needs a lot of homework.
Technical is not always the way to go. Its often based on simple assumptions that are going to go 50-50 so forex would need a lot of political news interpretation to determine trades.
You are right, speculation based market can't be without risks. When you participate in trading, any kind of trading, buying and selling, you are risking, depending on the risk there's a possible reward if your prediction is right, cause if you plan to trade and make profit you need to have good prediction skills.
I don't like forex trading, I never did. Crypto is much more accessible for people I believe, without kyc, more private, faster transactions, and when you have some coins that you hold for longer, possible profit can be huge.