If you hide/remove choices from a field drop-down/checkbox/radio button answer options, those changes would be reflected in any form that field is used in, as you experienced. If you have a field that want to show different options, even an abbreviated set of another field’s same options, you’d need to create a different field.
If you want both fields living on the same form and display other questions based on answer to the first question, you can do so using display logic (ie XYZ answers on question 1 shows a different subsequent question than if the user selected answers ABC in question 1).
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