Classic user error.
I see that the Tern Verge p10 has IS standard brakes. That is post mount brakes on a rotor size adaptor. The smaller wheels will afford a significantly stronger braking force at a given rotor size due to the proportional relationship between the two. It would be tempting to go for a smaller rotor to reduce the leverage that could be exerted & this have a more spongy/ progressive system that would be easier to modulate.
What you don't get is a lower need for heat dissipation. A smaller rotor will overheat & fade sooner, greatly increasing the risk of failure when you need them the most.
The bright side here is the rotors on Tern's website for your bike look like some super light weight ones that couldn't absorb much of a heat load anyway. You might be ok with a smaller road bike specific rotor with more capacity than the OEM one you have. Something such as a Shimano IceTech. Some of them have riffled cooling fins, others have so much material they look almost solid. You would also need a new IS mount adaptor to accommodate the smaller rotor diameter.
I don't know that I'd make that trade. I'm just saying that based on what the website shows in the pictures, that such a thing could be done.
__________________
I shouldn't have to "make myself more visible;" Drivers should just stop running people over.
Car dependency is a tax.