Have the same issue - WireGuard won’t properly connect upon reboot automatically on “GL-MT1300 / Beryl” with the latest firmware v3.215.
Using WireGuard client, kill-switch, vpn policies to disable for Guest Wi-Fi, use VPN for all processes, using custom DNS client which is behind the VPN (pi-hole).
@alzhao Do we have some news about this issue?
You managed to successfully fix the Beryl bug regarding the MAC clone (custom MAC addresses) last time. Actually, it seems to me you’ve fixed almost all the bugs. Good job, guys! 
Btw is this issue present also in GL-MT3000 (Beryl AX)? Thinking about ordering some newer GL.iNet routers once again. Thanks!