They had high hopes for the protests that they fueled. They thought they would last longer and become more violent. The crackdown by Iran government on Jan 8th quelled the protests quickly and succinctly. They didn't have the US military assets in place in the region before that and then decided without having the protestors fulfill the boots on the ground, it would be impossible to overthrow the regime with airstrikes alone. In fact BiBi likely asked Trump to not attack Iran since without a high chance of overthrowing the regime, Israel would take on another barrage of missiles from Iran and they didn't like how the Iron Dome faired the last time Iran attacked.

Iran quelled the protests with the assitance of Russian/Chinese signal jamming technology. 20,000 Starlink units were smuggled into the country from the period between the 9 day war (when the so called Iron Dome was found wanting) until the day of the protests.

They mostly quelled it with extreme violence and the threat of extreme violence. They sent out text messages on emergency channels basically telling people they will be shot if they protest and they followed through on that promise for a few thousand people. That will quell a lot of protests.