WireGuard for Android >= 0.0.20200322 supports Tasker integration now: https://data.zx2c4.com/wireguard-supports-tasker.png . Simply select the remote control option.
This may require some small tweaks in your Tasker. I've informed the generally responsive developer about this, and things should be moving along. Email their support, supp...@joaoapps.com , if you'd like to have a more up to date picture of what's up. Regards, Jason