How to securely create an offline wallet?

I still have not seen a good way to create an "offline wallet" to store value and not touch it in the foreseeable future.

First step is clear: Create a seed phrase with dice.

But then how do you create the first Bitcoin address from the seed? Popular opinion seems to be "Just use some offline device like a hardware wallet or an air gapped computer with a software wallet and then delete it.". But then you have to trust the developers of that software. Because they could have set up the software in a way that it creates guessable addresses. By error or because of malicious intent.

So I guess one would have to do the procedure on *two* devices with software from different teams. And compare the address they created to make sure they followed the same (hopefully secure) standard.

Has anybody here done this? When going the "air gapped with software wallet" route, what could be two separate implementations to use? Are they guaranteed to create the same addresses when given the same seed?