date_add id adding days. Today is 1st December and +35 days it gives 5th January which is first week of 2022 so result 1 is correct as returned by weekofyear function.
If you need just add leading zero the best way is to format it in visualization tool like / BI.
If you need leading zero in spark it will be have to be the string:
SELECT lpad(weekofyear(date_add(current_date, 35)), 2, '0')
It could be nice that date object is just format (date_format) as week number WW/ww but in spark is not included in date formatting: https://spark.apache.org/docs/latest/sql-ref-datetime-pattern.html