Need advice for teaching the communicative function of AAC devices for kids who exclusively stim on it

To start, I am neurodiversity affirming and there is nothing wrong with stimming. I know that the images, sounds, and feedback of pressing buttons are stimulating and exciting and I think that is a great thing. I have always been an advocate for allowing kids to stim on their AAC devices, just as many kids stim verbally. I work as an SLP in ABA clinics, and I always tell the ABA therapists and the parents that the kids are exploring the device and learning good navigation skills along with exposure to new vocabulary.

However, there are a few kids lately where I really feel stuck on being able to teach them communication with the device.

It’s important to note that these kids are still waiting for their trial device to come in, so they use my clinic device whenever I am there for sessions. For the last couple months of sessions, every session has exclusively consisted of the kids stimming on their favorite buttons without interacting with anything or anyone in their environment. I would really like to be able to model communication on their device, but they are possessive of it and often don’t allow me to model with it. I am worried that when they get their personal device in, that their ABA therapists and their parents will see it as a toy or a distraction rather than a communication device. I am worried that they will end up taking away the device or using it as reinforcement since it is so rewarding and stimulating for these kids to use. I have seen this happen a few times in the past.

All that to say, it is hard to teach the device as a means of communication to kids when they are only interested in the images and sounds of the device. It is especially hard to model things when they are possessive of the device. I am a new therapist as well. Is this just a normal part of the AAC process for many kids? Is there anything I can do differently? I want to make sure I am doing the best service for these kids.