I found good success with OpenWRT/Tomato and WireGuard.

The interface is bad when it comes to provisioning but it can be done with a QR code and once it works the native experience of turning on the VPN was just stunningly fast. In this day and age you expect things to be slow with negotiation and various unreliable steps but it was just amazing that I tap the VPN button on iOS and it's connected in a fraction of a second.