A VPN is enough for torrenting, as long as the VPN provider isn’t logging. I personally use AirVPN because they have port-forwarding but I’ve used Mullvad before. I also live in Germany and I’ve never gotten in trouble.
The guide you linked seems a little outdated, Jackett has been replaced by Prowlarr, which is there to have a central location to manage your trackers. If you plan to use Jellyfin, you should also use Jellyseer instead if Overseer. The *arr services are the ones that actually search for the files to download by using the trackers you set up in Prowlarr. You don’t need all the *arr services, I only have Sonarr and Radarr, which are for shows and movies respectively. I also have Bazarr for subtitles. AdguardHome is only for ad-blocking, might be useful to you but isn’t needed. Idk why that’s even in the guide. Flaresolverr is something I’ve never heard about and I don’t use it, so I can’t tell you anything about that. Heimdall is something I don’t need because I use YunoHost, which has a dashboard already but it might be useful to you.
Same goes for people who you convince to install Signal. They’ll end up never using it because they just forget about it and they’re not the ones who wanted to use it anyway. Being able to message people on WhatsApp through Signal would also make it a lot more easy to convince people to install it.