Don't squirt anything into a running engine! Ignore the idiotic YouTubers doing that sh1t, it's a waste of time and money, not to mention the risk of hydro lock if you dump too much chemical in at once.
Physical removal is the only way. Walnut blasting (or picks and chemicals) for the intake valves, and ultrasonic baths for the intake manifold and EGR pipes, anti shudder valve etc etc.