I’m highly skeptical of the idea that increased modability can turn around a game that lacks a large following. We’ve seen it with Starfield, where the release of the Creation Kit failed to increase the audience. Mods are built out of passion. Declining review scores and player counts don’t indicate that there is much passion for Civ 7 at the moment.
I hate to sound like a broken record, but anything short of fundamental changes to the civ switching/ages system isn’t going to have much impact. That’s how alienating that mechanic is. I think it’s fair to start asking the question about whether it’s worth alienating those who enjoy that mechanic in order to win back the people who hate it. I’m not sure what the answer to that question is.