They removed the Battery Management System from the battery and wired it up to power as an alternative to soldering directly to the small phone board. Turns out this phone also needs usb charging at the same time because otherwise it assumes the battery is dying even if it's not?
If anyone else is curious, they documented it here:
https://old.reddit.com/r/selfhosted/comments/1h7z9js/what_do_you_think_about_my_new_home_server/
I don't think so in your case. From their docs these features are only available for self hosted instances, so you'd have to host Traefik instead of Nginx and end up with a similar config as your current one.
Netbird/Tailscale are at their heart private LAN that you control that routes over the internet. They have some features on top to make DNS/TLS/Services/Tunneling easier. OP is using a service to allow external access to a host on their LAN.
If you wanted to hide your home IP you could either use something like Defelct or Cloudflare as a reverse proxy, or host your own reverse proxy on a cloud provider (either Nginx like you currently are, or Netbird's reverse proxy UI) and proxy it back to your local server over something like Netbird/Tailscale.
DDOS/Scraping protection would depend on the method you choose.