Not sure why you are buying a FS for mostly road work? I would have suggested a hard tail MTB, which are fine for trails and gravel tracks. If you have a bad back, would you go in the hills and hollows? FS doesn't help back pain! The shop will be happy as they are getting more £££
At the moment, while the roads are quiet, I'll be riding more on the back lanes than off-road. I don't really class fire tracks as off-road, so will be riding on these a lot now. Once we're out of lockdown, I'll then be riding more off-road, so the full sus will come into its own.
I'll use the next few weeks to build strength/ muscle memory back up, so hopefully by the time I go off-road again, I shouldn't have as many issues.
As Butch Cassidy said..... Ebikers have vision, and the rest of the cyclists wear bi-focals.... (slightly edited! 

No issues with this bike.