The problem really lies right there in the OP:
... the recommended navigation settings included disabling the options ("unpaved roads" and"narrow trails") under "avoidance settings ...
What exactly does that mean? Is it recommended to have unpaved roads navigable - or not? If not (as I rather suspect), then the 'avoid' option needs to be ENabled, not DISabled.
Incidentally I know that a lot of cyclists have 'avoid U-turns' selected - seems pointless to me since U-turns are usually very easy to do on a bicycle, even when they are forbidden to other traffic. If a U-turn shortens a route, then a cyclist should want to know about it.
Toll roads on the other hand - if you avoid toll roads don't you risk wiping out the whole of central London?