Demo Play vs Real Money Game. Need your feedback!

Hello everyone!

While playing in the demo mode I am winning money so often. However, once I decided to deposit funds and try for real and I lost everything. Provider, platform, and the slot machine was the same.
So my question is - Are they both treated the same?

I know that online casinos and especially virtual machines have become a fabulous pastime for hundreds of people all over the world, since they have access to them at the time they want, in a safe way and they don't need big amounts of money, unlike a physical casino.

My friend is playing in the one online hub, he told me that won the biggest jackpot playing buffalo slot. The goal of the game is the jackpot. The free demo mode has a jackpot of 300 coins. He did not recommend me playing slots with a Return to player of less than 90%, Bufallo slot has an RTP value of 94.85%,so maybe this is the reason.
So whom should I trust? Or maybe it depends on the platform?