
I have a deeplink URL from PBI to open a PowerApps page where I have a form and gallery. When PowerApps opens it will load the form and select and highlight the item from the gallery using the ID parameter in the URL perfectly as long as the Id between 1-101.
For example if the URL is PowerAppxyz?ID=100 Works
URL is PowerAppxyz?ID=200, the form will load with data for record ID 200 but the gallery will not select and highlight the record with ID 200. It just stays at the top on the first record with ID = 1 highlighted.
My data source is a SharePoint list and its has less than 400 items on the list.
Galleries load 100 records at a time, this is the standard behaviour. To show more records, you need to scroll down through the gallery.
To handle your problem, you could try filtering the galleries based on the ID and then your >100 ID record will show. If that isn't the UI you want for your users you could try filtering +/30 records either side of your ID so the users still see their record as well as other records. I haven't tested that but should work.