Can't connect to Heroku Postgres with ssl

I'm hosting a node.js backend and Postgres database on Heroku. After Heroku started requiring ssl, any requests to the database stopped working. I followed the documented fix here but I'm still getting errors. The request just hangs and eventually errors out as a CORS error.

"Access to XMLHttpRequest at [...] from origin [...] has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource."

Database requests work locally both in browser and Insomnia. I also tried making new Heroku projects but still run into the same error when making database requests.

Here is my db.js:

const { Client } = require("pg");

const client = new Client({
    connectionString: process.env.DATABASE_URL,
    ssl: {
        rejectUnauthorized: false
    }
});

client.connect();


module.exports = client;

app.js:

const express = require("express");
const cors = require("cors");
const app = express();
app.use(cors());
app.use(express.json());

// add logging system
const morgan = require("morgan");
app.use(morgan("tiny"));

const villagersRoutes = require("./routes/villagers");
const wakeRoutes = require("./routes/wake");

app.use("/villagers", villagersRoutes);
app.use("/", wakeRoutes);

/** 404 Not Found handler. */

app.use(function (req, res, next) {
  const err = new Error("Not Found");
  err.status = 404;
  next(err);
});

/** Generic error handler. */

app.use(function (err, req, res, next) {
  if (err.stack) console.error(err.stack);

  res.status(err.status || 500).json({
    message: err.message,
  });
});


module.exports = app;

server.js:

const app = require("./app");

app.listen(process.env.PORT || 5000, function () {
  console.log("Server is listening on port 5000");
});