Why wouldn’t you be able to get back the Swiss withholding taxes (35%)?
You simply need at least two lines, one for WV (tax value and dividends of securities without foreign withholding taxes) and one for DA-1.
If you also hold securities that pay dividends without any withholding (e.g. ETFs with an Irish domicile), you need to specify two income values on the summary line for WV, one with and one without Swiss withholding taxes.