Besides the examples you mention, research groups are now doing data assimilation for Mars (https://www2.physics.ox.ac.uk/research/geophysical-fluid-dyn... https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201...).
Other groups are testing and improving models for Jupiter and Saturn, as you mention, based on various remote sensing observations. (For Saturn, see: https://theoryofclimate.sciencesconf.org/conference/theoryof...).
All of these cases have allowed modelers to observationally test their models and model physics against non-Earth conditions. This work has been going on for a decade now, but it somehow has not reached the technically-aware audience.
The case of tidally-locked planets is another step beyond the above solar-system planets. Thank you for the references you supplied, in your original comment, on GCMs for this case.
I enjoy modeling, and I think it's useful, interesting as well as respectable work. But a little humility would in science is always a good things.
Regardless, it's more useful to point to particular areas of uncertainty than to point to a general miasma of uncertainty around climate modeling as though nothing can be learned. It doesn't really move any conversations forward.
Just because we can't predict when an individual hurricane will occur doesn't mean that we can't predict "hurricane season".
edit: Apparently it's not even certain whether the Sun will engulf the Earth or not!