Corrupted Nexus / corrupted zone are rare

I'm not sure why, but it takes forever to find them. I'm already farming t15 waystones, got 4 citadels and i'm stuck on the quest to clear a 10+ nexus. I can't find any corrupted zone. It's been 3 or 4 days since i did my last nexus.

The new map progression system was cool at the start where there was corrupted zone everywhere but as you move foward, it's way to slow.

Thank you