Not to brag, but I—GoldenArmorX—have beaten the first 5 campaigns on Ludicrous mode without cheats.
It’s tough, but most scenarios are manageable if your micromanagement skills are up to par and you know how to use counter-units… and—crucially—if you use plenty of strategic pauses to improve your micro.
The scenario that gave me the most trouble was the seventh one in the Fire Act (the fourth campaign, The Warchiefs). I even make a Thread to complain aggainst its difficulty, " FIRE-7 campaign Problem: Ludicrous Difficulty and Level design Changes IMPOSSIBLE", but at the end, i beat that horrible level, YEIH!!!