If you’re going steep, get all the gear you can to keep your cardio out of the red and your legs in one piece. Im not a good climber; I tried San Diego 18% gravel climbs on 42x42 gravel gearing and it sucked. I tried similar climbs on 32x51 MTB gearing and it was way less fatiguing.
I’d put a 34t little cog in there even if it doesn’t shift well. Maybe just get a separate cheap crank and 32t 1x chainring. That’d give you 12% more leverage in front. Maybe another 2% if you upsize the crank arms.
In back, I’d get a 34t cassette. You can use it as a trainer cassette if you don’t want to just run the 11sp one.
If you’ve got a short friend with 650b wheels in the right size with tires, that’d net you 6% more leverage with 28c tire.
That gets you 20% lower gearing. Beyond that, this might be an excuse to get a gravel/endurance bike so you can put a big cassette on it as well as put more rubber on the ground, which might be needed at these inclines.