In the end, I decided to first complete the deglaciated topography, and only then add the glaciers. Without further ado, here are the maps:

Elevations:
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Gradual (with bump map):
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This time around, I changed my Wilbur process a bit. Namely I upscaled the final map into 2x resolution for processing through Wilbur, then downscaled back afterwards. Overall, this does seem to take care of Precipiton Erosion induced-artifacts, eliminating the need to do manual blurring afterwards. Wilbur has some built-in features for that purpose as well (Dilate & Erode), which I've been reluctant to utilise due to the relatively low res of these maps, but perhaps with 2x resolution those might work out as well. Will have to experiment with that a bit.

@shadixdarkkon:
Aduhr has indeed had some ice ages in the recent past. Though the "northern corridor" is relatively easy to cross even with present-day sea level (at least for humans).

Next up, it's finally time to drop that big glacier on top (which I'm hoping will be a relatively quick procedure)!