You mean the country names?

No, I mean where you choose the AI difficulty. I want to change AI:Medium to Grok 2 for example

Weird... but I guess you can do that through modtext.csv modding.

https://forums.ea.com/discussions/command-and-conquer-franchise-en/what-filetype-do-mods-use/7279760

Figuring out the original IDs of all text to change is a bit of an issue though. I don't think there's any tool to open the original strings files. The map editor has the code to read it though, and I made a dump of that by tweaking the code in the map editor.

I uploaded it here, so this should help:
https://www.mediafire.com/file/ek447p8zcyt4ooy/CnCRemastered-alltext.txt/file
(Ugh, why does Steam block mediafire? So annoying.)

I'm assuming it's these lines:

TEXT_MULTIPLAYER_AI = AI
TEXT_MULTIPLAYER_AI_CASUAL = AI: EASY
TEXT_MULTIPLAYER_AI_EASY = AI: EASY
TEXT_MULTIPLAYER_AI_HARD = AI: HARD
TEXT_MULTIPLAYER_AI_INSANE = AI: INSANE
TEXT_MULTIPLAYER_AI_NORMAL = AI: MEDIUM
TEXT_MULTIPLAYER_AI_RANDOM = AI: RANDOM

Though might be these too; dunno exactly where you want to replace this.

TEXT_AI_DIFFICULTY_SETTING_CASUAL = Casual
TEXT_AI_DIFFICULTY_SETTING_EASY = Easy
TEXT_AI_DIFFICULTY_SETTING_HARD = Hard
TEXT_AI_DIFFICULTY_SETTING_INSANE = Insane
TEXT_AI_DIFFICULTY_SETTING_MEDIUM = Medium
TEXT_AI_DIFFICULTY_SETTING_NORMAL = Normal
TEXT_AI_DIFFICULTY_SETTING_RANDOM = Random

Note, these seem to be general GlyphX texts not specific to the C&C remaster, hence why there's an "Insane" in there that isn't actually used in the remaster.

Thanks!