I've just received a mail from Anne @SDE, and they are actually working on using IOSS, so there hopefully won't be any surprise fees and taxes from October or so for customers in the EU.[...]
I also asked SDE to use IOSS, so we could at least get rid of the unnecessary DHL fee when located in the EU. His assistant assured me she would talk to him about it, since I wasn't the first person to mention it. That was way back earlier this year. Unfortunately nothing has changed (yet?).