There is an option under "Tabs" called "Cycle tabs in recently used order", but ticking this option does not seem to affect CTRL-TAB behaviour. Is that a bug?

The above option doesn't seem to affect CTRL-TAB behaviour.
Then I spotted the CTRL-TAB keyboard shortcut, which is set to "Cycle Tabs Forward". However there is no keyboard shortcut for "Cycle Tabs in Recently Used Order. There IS, however a "Open Previous Tab" shortcut - this seems like a silly option, since just implementing "recently-viewed" order would make that option redundant. Recently-viewed is how many other professional apps work.

So please implement "recently-used" order - either as a Settings option, or (probably better) replace the silly "previous tab" keyboard shortcut with a "recently used order" shortcut. After all, with recently-used-order, pressing CTRL-TAB once does exactly that - it shows the previously viewed tab.