Demo account is not accurate because execution is instant or much faster than in live account that's why demo performance, especially decent returns of some scalping strategies is difficult to replicate on real account.
Leverage, in my opinion, should be used only when you know what you're doing and have a solid trading strategy. After opening a live trading account, beginners should avoid using leverage right away.
leverage could be more dangerous if there is no perfect money management. so build a strong trading plan.
this is a really challenging issue when using leverage , because this contains huge risk , so we have to be more careful when using it in practical.
when i was a beginner in trading i used no leverage in trading but right now beginners use too much leverage and at the end of the day they become loser.
the higher leverage you gonna use the more profit you gonna makes. The key is having a proper risk management to handle higher leverage
beginners should not use leverage in a live account , but they can practice it in a demo account to see the performance how it works.