Thank you so much, Peter!
This worked for hiding the question names (q1, q2, q3...), but I couldn't get it to work for the groups labels (group1, group2, group3). So I ended up forgoing the groups altogether and embedded the following URL to only show the first 3 questions:
https://survey123.arcgis.com/share/<survey_itemId>?hide=navbar,header,footer,theme,description,field:q4,field:q5,field:q6,field:q7,field:q8,field:q9,field:q10,field:q11,field:q12,field:q13,field:q14,field:q15,field:q16,field:q17,field:q18,field:q19,field:q20,field:q21,field:q22,field:q23,field:q24