Have you guys thought about Festgeld?
I got a call from the ZKB a few weeks about regarding our company account.
The current rate (12.07.2023) is 1.37% interest per year when you commit the money for 3 months. The longer you commit the higher the yearly interest will be. There are no further fees involved.
The only downside is that the minimum amount to commit is 100k. Unlike savings account there is no threshold where the interest will drop. To the contrary > 1 Mio. you get better conditions, at least that is what I understood. Unfortunately I am not in the position to commit > 1 Mio. 
Seems like an ok way to park liquidity.