Wow, thanks for that!
Now I can also see what I was doing wrong in my code 🙂
Yeah, ACF and their wp_options approach…
That's the only reason I don't use ACF. You're right, they didn't switch to term meta yet, not sure if it's on their roadmap either.
People do request the switch – https://support.advancedcustomfields.com/forums/topic/how-to-use-wp-term-meta-on-acf-the-easy-way/ – but I'm guessing they have to either maintain backwards compatibility or build a migration routine (or even both). None of those is a trivial task…
Thanks again for your help.