Serve other static `index.html` and assets on subpath(s)?

Description

I basically have 3 "apps", each are "static" bundles with their own relative assets.

my-app/
├── app2/
│   ├── app2.js
│   └── index.html
├── app3/
│   ├── index.css
│   └── app3.js
├── index.html
└── my-app.js

When I run serve -l 5280 my-app, I can browse to http://localhost:5280 and it serves my-app/index.html and the my-app.js just fine.

However, when I type http://localhost:5280/app2 in the address bar, the app2/index.html loads, but I get a 404 on app2.js :/

Library version

v14.2.0

Node version

v16.17.0