Help Me Cool Down

It's not just the fan speed that's down. It's the pump speed.

You need flow to cool the engine. Air flow and coolant flow. You've lost both.

Keeping the coolant in the engine is bad. You can't give up flow and not expect issues.

Agree, and looks like your fan is running a little deep in the shroud. Should be half of the fan blade in and half of the fan blade outside of the shroud.