I know, it's incredibly annoying, I'd love a dual SIM iPhone but you simply can't buy one in the EU other than a grey import from China without warranty. And no, neither of my two operators support eSIM.
I recently saw a Youtube video of someone who bought the sim card "daughter board" and sim tray from a Chinese iPhone and put it in a non-dual sim iPhone and it just worked. I can't remember the channel but it was from one of the fairly popular phone repair ones, so it should be pretty easy to find. The only real downside is that you have to open up your phone to swap the daughter board out and all that entails (the risk of breaking something, warranty, waterproofing, etc)