I have to add a follow-up to my comments from January above:
Since then I have ordered a fair smattering of stuff from Galaxus, and all these items have been delivered within the expected delivery window.
Had to return something for the first time - my fault, wrong thing ordered . The return system is easy to use, and postage was free.
I’ve even noticed that their book list seems to have expanded; a few more of the niche titles I look for seem to be available.
So my faith in Galaxus has been renewed. For now.
Best of all, though, I’ve kicked the Amazon habit.