[Emily]

The solution to this is actually quite simple! You can wrap your client ID in what’s known as a ‘zero width space’ character before you send it over to GA4. This special character (which is ‘& #8203;’ without the spaces) effectively convinces GA4 to treat the enclosed value as a string, even if it looks like a floating-point number. After you’ve wrapped up your client ID like this, it should show up in BigQuery as a string just as planned!

[Emily]

No worries at all! When you switch to GA4, it operates independently and won’t stop collecting data if UA stops. You do need to replace your old analytics.js code and keys with the new GA4 ones because they’re different systems. If data collection stops, simply, you’ll just stop receiving updates on user interactions with your site.