If you want perfection prepare for a long wait. I get your point that any kind of majority that is achieved by any means after initial polling, even instant runoff, is not the same as a first ballot majority. But Oklahoma uses a runoff now, and at least for primaries the only realistic option for reform in the foreseeable future seems to be IRV(and it’s not that realistic).
If you were drawing it up from scratch, what would be the election method you would implement?