This is not possible. You’ll either need to choose a different function or use the available hooks. What you want to do is why there are hooks in ACF that let you filter values, for example acf/load_value https://www.advancedcustomfields.com/resources/acfload_value/ and acf/format_value https://www.advancedcustomfields.com/resources/acfformat_value/.
Instead of calling your field and deciding whether to call the acf function or not you call the acf function and then you can filter the value returned after the fact.
