How to mix RTK Query apiSlice reducers with regular RTK reducers?

Question

I'm migrating some of our old Redux actions over from our original bespoke app to RTK Query and I've run into an issue which is likely just my lack of understanding of RTK Query.

I have an apiSlice as follows

import { createApi, fetchBaseQuery } from '@reduxjs/toolkit/query/react'
import { AUTH_SERVER, CLIENT_ID, REDIRECT_URI } from 'app/config'

const api = createApi({
  reducerPath: 'auth',
  baseQuery: fetchBaseQuery({
    baseUrl: `https://${AUTH_SERVER}`
  }),
  endpoints: builder => ({
    tokenFetch: builder.query({
      query: ({ code, code_verifier }) => ({
        url: '/oauth/token',
        method: 'POST',
        body: {
          grant_type: 'authorization_code',
          client_id: CLIENT_ID,
          code_verifier,
          code,
          redirect_uri: REDIRECT_URI
        }
      })
    }),
    tokenRefresh: builder.query({
      query: ({ refresh_token }) => ({
        url: '/oauth/token',
        method: 'POST',
        body: {
          grant_type: 'refresh_token',
          client_id: CLIENT_ID,
          refresh_token
        }
      })
    })
  })
})

export const { useTokenFetchQuery, useTokenRefreshQuery } = api

export default api

I have three issues I can't currently figure out:

1. I want to persist the user's auth tokens in the brower, (using redux-persist middleware in the original app - not sure how to integrate that here)
2. I need the results of tokenRefresh to overwite the original tokenFetch api call, (currently they are stored independently) and
3. I need to handle a tokenInvalidate action with a reducer that simply resets the auth state. (I can't see how I'd inject other reducers into this apiSlice)

How do I ensure that tokenFetch and tokenRefresh both push data to the same part of the redux state, and how do I inject a reducer in addition to the api calls to erase that state?