The Task Manager Utilization data confirms that your CPU is throttling. ThrottleStop shows why your CPU is throttling and what speed the CPU is running at. I will assume that ThrottleStop is still showing EDP throttling across all three domains.
Are you plugged in or are you running on battery power? If you are plugged in, is the battery fully charged? Some laptops will significantly limit performance when running on battery power or when the battery is being charged. The power adapters that many laptops with U series CPUs use tend to be barely adequate. Forced throttling is the solution instead of including an adequate power adapter.
EDP throttling is usually caused by one of the current limits being set too low. The FIVR section of ThrottleStop has been locked out by the BIOS so there is no way to try and adjust the IccMax current limits. Even if you were able to adjust IccMax, there might be a separate current limit that is being enforced by an embedded controller (EC) that ThrottleStop does not have access to.
In other words, there is no solution to fix your poorly performing laptop which is really too bad. The 8th Gen U series CPUs can run fantastic when a manufacturer leaves all of the various power and current limits unlocked. A similar 8550U in a Lenovo C930 can run indefinitely at full speed. It will only throttle when it gets too hot.