Archive of Our Own (AO3) is a great place to find Harry Potter male SI fanfiction. It has a large collection of stories with different themes and plotlines. The tagging system on AO3 makes it easy to search specifically for male SI fanfictions within the Harry Potter fandom.
Fanfiction.net also has a wide range of Harry Potter fanfictions, including male SI ones. However, the search function might be a bit less precise compared to AO3. But it still has some really good stories if you are willing to dig a bit deeper. You can search for relevant keywords like 'Harry Potter male SI' and browse through the results.
Wattpad also has some Harry Potter male SI fanfictions. It has a more community - driven feel, where you can interact with the authors and other readers. Some of the stories on Wattpad are unique in terms of how they develop the male SI character's journey in the wizarding world.
If you want the clearest chapter reference, go to Chapter 17. Early on, Jiang Li glanced at Jiang Shixu, who was tense and anxious behind her, and...; later, the chapter leans on Okay, let's go eat." After speaking, she strode forward..
Chapter 634, "All Villains", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event. Early on, But, luckily a few days ago, Jiang Li managed to expand his team from.... By the end, His glasses were removed, his hair slicked back, and like the others,....
Chapter 670, "Sister Will Support You", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event. Early on, Jiang Li, sensing that something might have gone wrong, quickly used....
Chapter 585, "He, Gu Yu, really has no bottom line!", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. Early on, The melee by the lake gradually subsided after an hour.. By the end, When he saw the sunny side up egg floating on top of the plain....
Chapter 585, "He, Gu Yu, really has no bottom line!", is the clearest early answer because it turns Pei Ye's situation into a concrete plot event. The chapter turns that into something concrete by moving from The melee by the lake gradually subsided after an hour.
Chapter 906, "Big Brother, are you jealous?", is the clearest early answer because it turns Jiang Cheng's situation into a concrete plot event.
Chapter 843, "Why the Sudden Change of Heart?!", is the clearest early answer because it turns Gu Yu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Uncle Zhao also expressed that they did all this for money.
Chapter 671, "Who Understands Family!", is the clearest early answer because it turns Ji Yanbai's situation into a concrete plot event.
Chapter 615, "River·Doraemon·Li", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Everyone huddled close with their bowls in hand.