I have a spouse from the US and we still have a US credit card that gives 1.5% cash back on all purchases with no annual fee. We put all non-CHF denominated purchases on this card. The forex spread for EUR is approx 0.6% and there are no foreign transaction fees, so we make approx 0.9% on each purchase. We could also do this for Swiss purchases too but for some reason that just feels dirty 
To pay off the bill each month I send cash to Interactive Brokers, covert to USD, make my ETF purchases, then withdraw (minimum 3 days after deposit per IB terms) the card balance to the US bank account.
Convoluted? Yep…but it’s routine for us now.
For any of you that have access to US banking, you could try this. The bank has never complained about our lack of contribution to their bottom line in the nearly 5 years we’ve been doing this.