IBKR recurring investment exchange rate effect

Hi, I have a question about investing with IBKR.

I have an automated pipeline to invest X CHF every month as ETFs (sending CHF to IBKR, then automatically buying Y $). I realized that due to the fluctuations in CHF/$ exchange, the amount of CHF that corresponds to the Y $ that was set up in the recurring investment can change monthly (and therefore not correspond to the X CHF that were initially transferred to the account).

Any idea on how to avoid this? Thanks in advance!