After reading up on here on effective ways to convert EUR to CHF, I went ahead and did so via IBKR.
After wiring myself back the money I got the following message:
" Dear Client,
Our records indicate that you have recently used your account (U********) to primarily convert deposited funds to another currency and then withdraw those funds. IBKR offers currency conversion as a convenience to clients who largely trade securities or commodities. **Please use your IBKR account for investing in securities or commodities, in order to avoid restrictions on your ability to convert currency."
I guess it’s not so much a good option anymore then…