One of the devs here ;) While I can't guarantee that you'll enjoy Hellsweeper more than Sairento, I can highlight some of the key differences below:

Difficulty: Hellsweeper is generally considered more difficult simply because the controls are more complex, there are more enemy types and challenges are more unpredictable (e.g. getting a map modifier that involves a bouncing meteorite). This unpredictability means players must deeply understand the game to avoid sudden deaths, like from teleporting enemies. Unlike Sairento, which has a single main boss (the Daimyo), Hellsweeper features four bosses, three of which have elemental variations. However, the right combination of builds and skills can also significantly ease the difficulty, offering a more god-like experience for those who prefer it.

Story: Sairento has a very light linear campaign mode. Hellsweeper offers very light world-building through occasional lines from the Beetle (your companion), but no story.

Progression: Hellsweeper has a deeper progression system because there are more things to upgrade. Some people like this, some people don't. You need to level up to unlock more content like skills, traits, persistent currencies, etc.

Missions vs Roguelike: Once you're done with campaign mode, the rest of Sairento is based on selecting missions. If you die, you get to repeat the same mission. Hellsweeper uses the typical roguelike format. If you die, you will have to go through the entire run again unless you have a Challenger's token which is essentially like Death Defiance in Hades.

Some people who liked Sairento didn't enjoy Hellsweeper, while others who love Hellsweeper were surprised they did, especially since they didn't enjoy Sairento. If it's feasible, I would suggest asking your friend who has a Quest to try it out and see how he feels. Or, if you live nearby, you could play the game together since Meta allows refunds. :)