After doing research, I have come to the conclusion that this take is both misleading and unprovable. There are sources that support both sides of this debate, allowing for both sides to prove themselves as "more right". Scenarios and claims that involve people's emotions are usually subjective, being that different people feel different things, react differently to situations, and handle hardships in different ways. Forbes gives their take on this, saying that "relationships offer a happiness boost, but only the good ones" (Forbes, 2023). With that being said, they also state later in their article that "Happy people may be more likely to enter relationships in the first place, making it even more difficult to know if relationships make people happy or if happy people naturally gravitate toward relationships" (Forbes, 2023). This simply shows that this claim can be formed and shifted to fit all kinds of perspectives, but that there is not one single opinion on this that can be completely proven right. I know people who really do enjoy being single and thrive in that kind of independent state of living. On the contrary, I also know people that thrive when they have someone to love, take care of, and grow with. This all completely depends on the person, their current life situation, and what they want for their future. This claim is misleading and although it can be correct for some people, it is incorrect for others.
References:
https://www.forbes.com/sites/traversmark/2023/10/27/a-psychologist-answers-the-would-i-be-happier-single-question/