J.K.
My older son (Add/PddNos) did okay when he was 4/5 years old, but a couple years later he realized that his peers were mostly too immature. He was never one for typical kid shenanigans.
In 3rd grade, he made one very good friend who lived in our neighborhood and was 2 years older. When that boy moved away the summer before 8th grade we were both sad about it. He did not become close to any other kids until 10th grade. He met two boys in one of his clubs. They have continued to hang out once a week in the summer. Unfortunately, they were both Seniors and are off to other cities for college in a couple weeks. I hope he is able to make a new local friend when the school year begins.
My younger son was really into Polly Pocket when he was about your son's age. One day, one of his friends came over and saw him playing with Polly and GI Joe at the same time. The friend told him, with a sneer, "Those Pollys are girl toys. I'm not going to play with you if you don't throw them away!"
My son calmly said, "Okay." and turned his back on his friend. Friend's jaw dropped and he learned that my son had no time for his nonsense. A couple minutes later and they were both playing with Polly and GI Joe. That is what happy confidence looks like.
He is starting high school this fall and is quite a popular social bug. He doesn't play with Polly Pockets anymore...but he kept them in storage. It's the one childhood toy he wanted to keep.
It is not possible for a kid to be confident and happy while hiding who they are and what interests them. That causes shame for their interest, which leads to thinking there is something wrong with them as a person for having the interest.
It is better to have one real, high-quality friend than it would be to have twenty friendly people who don't even know who you really are. Your son needs to know to stay true to himself and to not accept low-quality friendships.