Shading losses can be huge.
To give you an idea of efficiency loss of a shadow, I have 100 watt panels that are about 42”X 20” that output 5 or 6 amps each in maximum sunlight. To test the panel, I will put the shadow of my head over the panels, and I see it drop to 1 amp. That’s an 80% efficiency loss. Also, on a cloudy overcast day, my panel output will drop to 1.2 amps per panel, or 75% less energy produced.
In northern latitudes, south facing panels are always a better choice, barring shade. I’ll call them niche production, but there could be other areas that produce more power than you’d expect. For me this “niche” is my 400 watts of portable panels that I point into the sun three times a day. With the better morning and evening production and the 30 degree tilt of these panels, I typically get more production out of these than my other 950 watts of flat panels.
If you start looking for places that get sun year round, that could make some energy. Also, for me for the winter months panels on my RV walls look like it could produce a bit of energy on an east and west facing wall At the beginning or end of the day. To me that means a K-cup coffee earlier in the morning.