Do you have any plans to make high-definition images later?

Nope. I don't have tool for that and Hi-def images are not in free to play version.

https://mods.factorio.com/mod/erm_zerg_hd 5hinzou made this possible!!!

When start new world, there is no enemy on the map?

It's likely caused by RSO settings. Please refer to mod-compatiblity doc for details.
https://github.com/heyqule/enemy_race_manager/blob/main/Mod-Compatibility.md

I don't see Zerg on Nauvis. There is only biters. Why?

ERM 2.0 does not change nauvis enemy by default. You can change the nauvis enemy generation to mixed / 2ways / 4ways in start up setting.