How to track App Store rankings
A ranking is a snapshot. A trend is more useful when you compare the same search consistently.
Set a baseline.
Choose a short list of terms that describe your app and record where it appears in each important country before you change your listing.
Compare like with like.
Keep the keyword and storefront the same when you review movement. Switching countries or terms changes the question you are measuring.
Look beyond one jump.
Search results move as competing apps change, and a single observation can be noisy. Look for sustained movement, then check whether impressions and downloads in your own App Store Connect data move with it.
Do not confuse correlation with cause.
A ranking improvement after an update is useful evidence, but it does not prove that one title, subtitle, or keyword change caused the result.