If I use 100 leverage, and I have 10K USD in the demo account, will I use 0.01 lot because it is 10% of 100.000 USD? Or with leverage it will be 10 times more?
Everything you say is correct. If for $100,000 a lot of 0.1 is recommended, then for $10,000 a lot of 0.01 is recommended. Leverage of 1:100 means nothing in this case with a maximum drawdown of only 3%.