My combo:
ZKB: main account (e.g. salary) + shared account with GF + custody account (just to hold and to have it as a Swiss institution) + debit card, which I absolutely never use (but it was free). Always have roughly 1k on the main account to be able to Twint stuff - otherwise, I am only paying with the credit card.
WillBe: emergency account/savings account. Abroad and can only be transferred to an pre-defined account in your name. Had always very good interest rates (at the moment 1.3% p.a.).
IBRK: trading + holding only
Neon: Fx transactions only
Amex Gold: I earn a lot of these MR points which are useful for flights, hotels, etc. I am diversified with the MR points, since - in contrary to Miles and More - there are several options how you can use these points. I will downgrade it to Green/Classic in two years, since all the insurance components are already covered by TCS. I just took Gold because of a special offer with bonus MR points. Nearly do not have issues when paying with Amex (living in Zurich).
TCS Mastercard: free and there are some benefits like discount for petrol or when charging a car.
Swisscards Cashback: shared cards with GF for shared spendings.
Always interesting to see, how subjective the optimal package is, since I am pretty sure, that one would not take the Amex Gold, e.g. Really depend on one’s needs, obviously.
But as long as someone is using Revolut/Zak/neon/whatever for FX transactions and a reliable main bank account, you can’t do much wrong. There are other componentes which have a higher impact, in my opinion (e.g. health insurance premium, costs for food, rent, etc.).