My guess is that if ACF could manage a forum that the developer would be using it here. This site actually uses https://wordpress.org/plugins/bbpress/. I’m not very familiar with bbpress or what it’s capabilities are. To echo the answer you got in the forum you linked to, I have not seen anything like what you’re looking for as a WP plugin. I’m sure that with enough work you could use ACF to assist in building something like that, but it’s not something that ACF will do.
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