2,000 lines? 200,000 lines? i think "2000k" would be 2,000,000 (which is beyond the limit of Excel)?
is it that many lines on your survey tab?
or your choices tab?
Most mobile devices released in 2019 or later can handle lists of 50,000 or more without slowdowns.
if you have complex survey logic, it might be causing a problem. here's an example where the formula in a repeat_count was breaking a form under certain circumstances:
is there a particular action (like saving, or swiping back to a previous question) that you can pinpoint as causing the issue? or a particular point in the form when things tend to break?