You'd think with a series as visually chaotic as 'Helluva Boss', finding reader inserts would be a no-brainer, but the quality varies so wildly it's a real hunt. My strategy always starts with sorting by reading lists, not just overall popularity. Someone bothered to curate a list titled something specific, like 'Blitzo Angst' or 'Stolas Slow Burn', has already filtered a lot of the generic stuff.
I also find the tags matter more than the summary sometimes. If a story's tagged just 'Helluva Boss x Reader', it's often a fluff one-shot. But if you see specific episode tags like 'Loo Loo Land' or 'The Harvest Moon Festival', the writer is usually pulling more directly from canon events, which tends to mean better character voices. The ones that just throw every character's name in the tags as a pairing are almost always a mess.
Ultimately, I've had better luck following authors who write good OC-centric fic for the show; their reader inserts usually have more thought put into the narrative voice because they're used to building a consistent perspective that isn't just a blank slate.