.NET C# Performance Improvement

Hello and thank you for joining such a wonderful Journey,
I'm looking for a senior developer C#,
for a 1 year of work.

Project Info
.NET 7
DB: MSSQL

This Current Job has 3 issue to solve,
it seems simple BUT we need a True Expert to work on this.

Issue 1: Performance! API is set to limit=100 (by Design)
APi Response takes 15 - 30 Seconds!
API: /api/v1/stories?catalog=Relationship&page=0

Your mission: Improve Performance so data fetch will happen in 1 sec.
i'm also adding an Example of a Stores Procedure
you incase you would like using it.

Issue 2
Change Hard Coded to Dynamic.
When? When user Post new Story.
Bug: When user Post new Story we Pass "EN" as the Story Language
Solution: Pass Story Language According to User LanguageID

LanguageId table: All Languages
Language Per User: Table Users.