There is an updated pull request by Skirmisher against master on the void-packages repository

https://github.com/Skirmisher/void-packages upstream-master
https://github.com/void-linux/void-packages/pull/19767

yggdrasil: add service changes from upstream systemd unit
yggdrasil will fail to start if the `tun` kernel module is not loaded. Upstream modified their [service file](https://github.com/yggdrasil-network/yggdrasil-go/blob/4b16c325a3d90d97df208457bc35d499249f8146/contrib/systemd/yggdrasil.service) to first attempt to load the module before starting the service. They also opted to drop capabilities to CAP_NET_ADMIN and CAP_NET_RAW, which I saw fit to include.

A patch file from https://github.com/void-linux/void-packages/pull/19767.patch is attached