What3words - what's the best way of using this for off-road navigation?

I’ve been riding at the Quantock hills, trying to navigate through Strava maps uploaded onto a Wahoo Roam. DC Rainmaker is accurate in his view that it’s a good cycling computer, but a poor navigational device!
We are starting to ride routes from memory, but sometimes get lost. I think what3words might be useful to have as a back up, but it would be important to link in with elevation changes as there are some big hills, with some routes being unrideable.
There are a few map apps which are affiliated with What3words. I was wondering which one to try as they all seem quite involved.
Has anyone found a good set up for navigating this type of terrain?