Adverts feature is not there in my game after 9 years.

That is not a lie because nobody at King claims that any more! I have NOT heard that claim since the early days of Candy Crush. Levels above 14,000 are quite definitely not passable without boosters and not meant to be passable without boosters. The game has changed since the early days and players at the top levels are supposed to play boosters to pass them. That is now incorporated into the level designs and the only way to suceed in this game.

What they mean by it being a "free game" is the fact that free boosters are available to gain with events, and there are also a few events that give out free gold to anyone by passing previous, easier levels. So in theory players can succeed just by playing all the events to gain gold and boosters and using these. However, I doubt this is possible for levels above 14,000.