You can use the Prisma Validator API along with some typescript features to generate types for your query.

For the findMany example you mentioned

import { Prisma } from '@prisma/client'

// 1. Define a User type that includes the "cars" relation. 
const userWithCars = Prisma.validator<Prisma.UserArgs>()({
    include: { cars: true },
})

// 2: This type will include many users and all their cars
type UserWithCars = Prisma.UserGetPayload<typeof userWithCars>[]

If you simply want to automatically infer the return type of a prisma query wrapped in a function, you can use PromiseReturnType.

For example:

import { Prisma } from '@prisma/client'

async function getUsersWithCars() {
  const users = await prisma.user.findMany({ include: { cars: true } });
  return users;
}

type UsersWithCars = Prisma.PromiseReturnType<typeof getUsersWithCars>

You can read more about this in the Operating against partial structures of your model types concept guide in the Prisma docs.