On Windows 10, after installing the latest OpenSSL v3, npm run start:https resulted in this error:

node:events:505
      throw er; // Unhandled 'error' event
      ^

Error: RSA PRIVATE KEY not found from openssl output:
---stdout---
-----BEGIN PRIVATE KEY-----
...

Basically the output text from OpenSSL seems to have changed, hence the self signed cert cannot be parsed. A quick hackish fix for this is a one line change to node_modules/pem/lib/pem.js, line 77:

FROM:
openssl.exec(params, 'RSA PRIVATE KEY', function (sslErr, key) {

TO:
openssl.exec(params, 'PRIVATE KEY', function (sslErr, key) {

After that, it starts right up and is useable on my VR Headset now that it has SSL in place for WebXR.
Hopefully this saves someone else some time too! :)

• v1.3
• Windows 10
• OpenSSL v3.05 (Lite) installed from https://slproweb.com/products/Win32OpenSSL.html