You were in the right place - meta’s the best place to discuss it. The problem is the specifics are still fuzzy. In your current post, you talk about raising the char. limit on the site-specific “off-topic” reasons, but the example you give “your question has an answer” isn’t an “off-topic” reason, or shouldn’t be - it’s the duplicate question language.
If you think dupe close reason language can be improved, I’d put up a meta post focused on that. If you think that the site specific OT reasons on Ask Ubuntu (pic below) could be much more polite if more chars were available, give specific examples.
Yes, that’s why there’s some confusion and negative reaction to the post, I think. There are “top-level” close reasons on all sites: “Too Broad”, “Overly Opinion Based”. “Off-Topic”, etc. For “Off-topic” ONLY, there are then individual sub-reasons for each site.