How can I filter entity titles in an autocomplete form and use the title as context for a View page?
Here's how I solved my problem:


Added an ID field (the ID from the source I'm pulling/validating player names) to my variation.  On creation of a variation, I store the ID in the field when the user selects the player name during product creation, e.g. "Barry Bonds" is ID 35456 in my source.
I'm using a regular autocomplete route in my form instead of an entity_autocomplete.  My autocomplete handler does an entity query on cards (product variations) that are active and match the player name.
After the player is selected from the autocomplete, on form validation, I re-select the player to get the ID.
On form submit I pass the ID with the URL to my views page as a contextual filter, where it expects it as a field value in the URL, e.g. "/player-card-search/35456".


Creating the new ID field in my product variation feels redundant, but it got me to the solution.