Hey there,
Nope - Discord won’t ‘know’ if you use Redact.dev to delete stuff. They have rate limits (restrictions on the amount of actions you can take in a period of time) - but Redact respects these limits.
Thousands of people have used Redact for Discord and had no issues 
When you run Redact, Discord interprets the actions as standard user actions. Basically, if you went through your Discord and deleted 1000 messages manually, it would leave pretty much the same fingerprint as Redact.
As long as you only run one version of Redact at a time, and don’t engage in spammy behaviour, you shouldn’t be at risk of any suspension or bans.
Specific servers might have their own policies re: deleting messages though - read server rules before deleting from them, if you’re concerned.