Picking a new game to hardcore nuzlocke

I recently finished my first ever hardcore nuzlocke (and first nuzlocke overall) in Modern Emerald, which is basically the base game with some QoL changes. I managed to do it on my first attempt, although I did have every Pokemon exactly at the level cap for each gym battle so that could have made it a bit easier. I had 6 deaths before the E4 (4 during grinding, 1 on Norman and 1 on Winona) and 3 during E4, which I think is not that bad. However, now that I passed the tutorial I'd love to test myself on something harder. Please give me your recommendations based on my experience so far, so probably quite a bit harder than base Emerald, but also not something I'll have no chance on beating. I'll choose the suggestion with most upvotes when I wake up tomorrow morning (assuming I'll get some recommendations by then). I'm assuming it'd be mostly fan games, which is more than welcome, as the only official game I have is Ultra Sun.

TL;DR: just finished my first ever hardcore nuzlocke (Emerald) and need something harder, but also possible to finish