I have a somewhat different perspective, but one that I believe is popular among the Civ fanbase. Civ 6 released as a much fuller game than Civ 5, but the latter's expansions really completed it, whereas the former's were more just standard, middling new content.
Personally, while I do like both games quite a bit, I'd much rather return to Civ 5 at this point - not that I've played much of either in the past couple years.
"I believe in a universe that doesn't care and people who do."
Hylian hits dizzying heights others daren't aim for. He's the Celeste of Board 8 users.