While simple config edits (autoexec.cfg) are generally safe, executable programs labeled "Delay Reducers" are high-risk. Valve defines "cheating" broadly, often centered on the unauthorized modification of game files or memory injection. Many players who downloaded "Universal Delay Reducers" from forums found themselves VAC banned, not because they wanted lower ping, but because the software they used injected code into the game memory to achieve it.
Cutting the Lag: Understanding the ‘Delay Reducer’ in Dota 2 delay reducer dota