This isn't an issue of technical merit. This is an issue of the lack of emotional safety brought on by the bullying. The phone is only one area that kids can be cruel in. The pressure to conform will be very high as the kids will ostracize him from iMessage group chats for "turning their bubbles green" and essentially being the individual that brings a neutered media experience to the group.

There is an active negative selection pressure that the kids are exercising. "Lame" is really just the tip of the iceberg. So you reply, "it's not lame! look at all these cool things you can do." This is very invalidating for your son.

Others have mentioned things like self-confidence, but I'd beg to differ. One can't just pull confidence out of a magic hat. These kinds of character traits are developed over time and circumstance in small amounts so that the mental activation energy of getting over a give "hump" is significantly reduced. And also confidence is a similar solution to the way, "getting an iphone" is a similar situation to getting bullied.

Sure, the peer pressure is unacceptable and people shouldn't be judged on their merit, but what your son needs isn't logic that proves the principled stance. He needs you & (other parent if they are available) that can listen to his personal struggle of what it feels like to deal with the situation (without offering solutions like "side-loading is awesome!").

Once he has an authentic, non-judgmental, supportive, not-providing-solutions outlet for the struggles he's facing, then you as a parent can help him process what is going on. And in that process, you can model what a healthy response looks like. Without that modeling, and a framework for being able to articulate rebuttals and defend himself, "just having a capable phone" is a very dismissive approach. He legitimately has an Everest of a social mountain to climb not being an iPhone user.

As adults, getting judged by some unimportant people in our lives is not important to us, but as kids, his school, his "friends" are likely a HUGE part of his life. And being able to participate in those social circles is a huge part of the quality of life and satisfaction he likely receives from his peers. So it's important to be able to understand what about his inner world is important. And it's important to validate that his inner-world is seen & heard, and based on what's been seen & heard, that he feels accepted.

If this wasn't an issue for a while, it could be that he wants to join a particular social circle because maybe he's interested in a girl from that social circle. It could be that he looks up to someone in a particular circle and wants to be accepted by them. It could be that he feels that he needs to obtain a certain amount of status by associating with certain kids (he won't actually word it this way). So it's important to be able to delve into what's really happening, how it's making him feel, that his feelings are actually legitimate & OKAY, and what coping mechanisms are necessary to prioritize the right things.

I don't have any helpful direct youtube links, but I would highly recommend looking through the Youtube videos of HealthyGamerGG, who is a Harvard trained psychiatrist, but makes a tremendous amount of the challenges that kids go through, very accessible to understand with both kids & adults alike.