I kinda doubt Zelda will affect Horizon the same way Overwatch killed Battleborn
For one thing, they're exclusives for completely different consoles which means different audiences.
When it comes to coverage, Horizon's review embargo was recently lifted 1 week before launch and with the current metascore of 88, Sony has clearly planned ahead to make sure customers would pre-order the game with the guarantee that it's completely worth it.

Comparing apples to oranges.

- It's not a same day release
- They don't share a gaming system
- Targeted at hugely different audiences