By that I mean changing the text with variables as a string, rather than booleans in a config. Things like intel_corrupted_notification put_problematic_frame_to_message put_analysis_result_to_message can also be variables.
Preferably in a language string, though considering generated_msg_lang it might already be partly there.

All message text can be customized; it's already in the language files.
It's better to describe exactly how you want to customize the message.
Currently, there are a lot of logic and optional conditions.
What do you mean by "variables, not booleans": intel_corrupted_notification, put_problematic_frame_to_message, and put_analysis_result_to_message. These options either appear in the message or they don't. I don't see a third option. The text inside them can already be customized.

So if the message is currently this

Modpack Name crashed. The logs have been uploaded to `mclo.gs`:
[latest.log](<https://mclo.gs/abc>)
[crash-2025-10-03_20.18.29-client.txt](<https://mclo.gs/def>)
[PrismLauncher-0.log](<https://mclo.gs/ghi>)

it could be described in translation strings like this*

"message_text": "$MODPACK_NAME$ crashed. The logs have been uploaded to '$LOG_PROVIDER$':\n$LOG_LINKS$\n$INTEL_CORRUPTED_NOTIFICATION$\n$PROBLEMATIC_FRAME$\n$ANALYSIS_RESULT$"
"message_link_format": "[$LINK_TITLE$](<$LINK_URL$>)"
"message_link_separator": "\n"

Therefore the format would be fully customizable and reorderable.

* I didn't check if the variables exist or are named as such