A way to kill Reinhardt?

I just thought of a way that may kill reinhardt ,but just know that I didn't read whole novel so most of my informations are from wikis.

First of all ,Reinhardt have 4 main powers:

1-his gate that absorbs all mana and save it with enormous amount which :

a)enchance his physical abilities to be harder than steel and faster than light.

b)render magic useless against him.

c)sending normal destructive attacks with pure mana.

2-all and any divine protection he needs which make him immortal.

3-dragon sword which can destroy anything completely.

The way to defeat:-

1-seperate him from the world using that magic circle to take off his divine protection making it possible to hit him and kill him permanently.

2-having regulus fight him since he can pare with him ,hurt him and is not worthy for the dragon sword to be used against.

3-killing reinhardt with the Life Sword to destroy his soul so that it won't return to Od Laguna making it immposible to resurrect him in any way that we don't know about.

Proofs to support my theory:

1-Author stated that reinhardt won't be able to defeat regulus without subaru.

2-it was stated that someone will be able to defeat reinhardt (it is a spoiler so we don't know who) if all his divine protections were taken off.

I want to hear your opinions about this method and please correct me if I am wrong about something.