Current navigation bar/Quick launch cannot be restored after Enable-SPOCommsite

[icelava]

I recently got SharePoint administrator role and on reviewing our existing sites found that the root site was a classic team site (appears to be before the Apr 2019 cut-over). Judging from the old and new home.aspx pages, I think somebody in the past updated to it be a modern communication site.

However, unlike brand new communication sites, I notice this one had its current navigation bar on the left vertical slice. As a root site, its global navigation bar at the top appears just fine. Eventually, I disabled the Enable Quick Launch setting to hide it.

Now to be sure, I ran the Enable-SPOCommsite cmdlet to observe any differences. It created another templated home page which I reverted back to the existing one. But then, when I look at its Site Settings > Look and Feel section

• There's no more Navigation Elements sub-section to re-enable the Quick Launch; so I cannot see if it appears horizontally or vertically.
• All it has is a Quick Launch sub-section to adjust the navigation items/links. But that is useless since it does not render anymore.

Is its current navigation bar gone forever?

[#2 · Accepted solution]

Talk about eureka right after pressing the post button.

So I referenced the other test hub site settings, copied its /_layouts/15/navoptions.aspx sub URL and pasted it in for this root site, and voila the setting page appears for me to re-enable (and render horizontally).

After tinkering with various classic/modern, sub-site/hub site/associated site combinations, I must state the Site Settings admin UI is horribly messed up and inconsistent.