Duplicate user URLs

Well the easiest implementation (Using regex since you mentioned it) off the top of my head would be:

// Using express here, first thing that came to mind
const express = require('express');
const app = express();
app.get("/Some-URL", (req, res) => {
    res.send("Hi");
});
app.use((req, res) => {
    if (/^\/some-url$/i.test(req.url)) {
        res.redirect("/Some-URL");
    }
});
app.listen(() => console.log("Server Running"));

Yes, for example:

// Using express here, first thing that came to mind
const express = require('express');
const app = express();
app.get("/Some-URL", (req, res) => {
    res.send("Hi");
});
app.get("/some-url", (req, res) => {
    res.send("Lowercase, eh?");
})
app.listen(() => console.log("Server Running"));