If you have the Brave Browser installed on your Windows devices, then you may also have Brave VPN services installed on the machine. Brave installs these services without user consent on Windows devices.
Brave Firewall + VPN is an extra service that Brave users may subscribe to for a monthly fee. Launched in mid-2022, it is a cooperation between Brave Software, maker of Brave Browser, and Guardian, the company that operates the VPN and the firewall solution. The firewall and VPN solution is available for $9.99 per month.
The entire premise is for a package/manager to create a running/permanent service that will be started after boot AND does not require user intervention (for the avoidance of doubt, enabling the systemd service counts as intervention).
One way to do this is to create the service file and do the symlink to a folder that systemd automatically runs on boot. For both user and system systemd files you require root to make these modifications.
Another way is to create a Desktop file in the path I shared.
If you have more ways I’d be happy to hear them.