The current SBI Corporate yield is 0.93% p.a., which seems to be the highest yield of the SBI index family. The current duration is 4.4 years. I think the next step up would be Swiss Real Estate funds.
If the investment doesn’t have to be liquid, some Kassenobligationen are a bit better than bond funds. 2y Cembra is at 0.75% p.a., 10y 1.25% p.a. That’s fully locked but at least you also get the deposit insurance of up to 100k. Some special savings accounts might also still be better than bond funds.
I guess you’ve already seen Short guide to CHF fixed income options.