>>klipit+(OP)
I used ngrok when it was the to-go answer for serving localhost (temporarily, not permanent) to the public, but the last time I searched for alternatives I stumbled upon the following jewel.
> tailscale funnel 3000
Available on the internet:
https://some-device-name.tail12345.ts.net/
|-- proxy http://127.0.0.1:3000
Press Ctrl+C to exit.
I've tailscale installed on my machine anyway for some connected devices. But even without this would convince me using it, because it's part of the free tier, dead simple and with tailscale it's coming from kind of a trusted entity.