I have a Fortitude Adventure. Commuted on it as stock for a few days, 20miles round trip. It was fine. Roughly 2 mins each way slower than the Day One Cross SS I’d usually commute on. Obviously you’d expect a geared bike to be quicker than SS on a relatively flat ride but the fatter tyres slow it down.
The Alfine wasn’t 100% so that’s back at Shimano for a fix but once the bike is back on the road I plan to use it more for commuting.
I’ve also had the Fortitude off road once, and it worked well, but the places I ride off road are very hilly and the gearing was all wrong, but a 20t at the back should sort that.