You can create filters based on tag prefix using the following steps:
Go to your Shopify Admin Store > App > Searchly.
Click on Filters and select Manage Filters.
Click on Add New Filter.
Write filter title in Title field, select Product Tag Prefix in Created Filter Using field.
Add Tag Prefixes in the Product Tag Prefixes field and click Save.
Now run data sync by clicking the Data Sync.
Please see this example for reference:
Filter with Tag Prefix: