Hi Aeroman76,
So far, I have tested 3 variations of Stridas on an uphill road this year. about 6-10 kms going uphill. I’m not sure about the grade of the steepness but I have tried the Stida 5 or LT is a capable climber as well.
The other Strida I have tested are SD 16" wheels and SD with 18" wheels.
If you are regularly riding uphill eventually your legs would get used to it. I used to change to low gear on a route I take to visit my cousin but now I can use the high gear even on the slight uphill.
Another technique is to pedal like that of road bikers where you use the toe part on the the pedal and not the arch of your foot.
Happy riding.