I think you've answered your own question. The documentation you've linked to is the best place to start, and there is no more "portable" way available, unless you write some extra code to work off the name of the field (which is risky because you can change the name of a field very easily)
I’m a designer on the Jira team. For a long time, I’ve fielded questions from other designers about how they should be using Jira Software with their design team. I’ve also heard feedback from other ...
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