The video below highlights how infomercials invent silly "problems" that people supposedly have - a bed too high for a small dog to jump onto, or accidentally cracking an egg into a stove's burner - so that they can sell TV viewers their "solutions."
Very few people would think such things are problems in their life until an infomercial tells them these are problems, so that advertisers can sell "solutions" - a stepping stool for small dogs or a guided egg-cracker - for only 3 easy payments of $19.99!
In such cases, both the "problems" and the "solutions" are rather silly, but the sale pitch works on enough people to justify the cost of the ads.
Christianity does much the same thing.
Consider the billions of people living out their lives: pursuing passions, getting married, raising children, enjoying the planet, struggling toward their goals. If somebody didn't tell them their life was meaningless and purposeless without God, would that ever occur to them? Probably not. We all find a great deal of meaning and purpose in life without God.
So Christianity must first convince people they have a problem. That the meaning and purpose they currently find in life doesn't really count unless it has been given to them by a cosmic dictator. That is a rather silly "problem", but Christians make a strong and ever-present pitch in favor of it.
Then they propose a "solution"... for only 500 monthly payments of 10% of your income! (Plus lots of prayer and Bible reading and other sacrifices.) And what is the solution? Worship and serve an invisible cosmic dictator, who will somehow "give" you meaning and purpose that really counts.
When Christians tell me that without God I must not have any meaning or purpose in life, I tell them: "Sorry, I don't have that problem."
And when they go on to tell me what their solution is, I say: "I don't see much value in your solution, either."
There is plenty of purpose in life without God.