We have always had low pressure in our Grohe Ladylux Café kitchen faucet, but lately it has become completely unusable. Pressure is low for both hot and cold, but significantly lower for hot. Faucet is about 7 years old.

Hot water pressure going into the faucet is fine.
Water pressure is low even with the spray head off.

From reading this forum, I am guessing the problem is either the quick connect coupling (we have the red one with the integrated flow regulator) or the cartridge. Tried cleaning the quick connect but that didn't help. Is there a way to completely remove the regulator from the quick connect without otherwise affecting the faucet? I realize it also provides a backflow function, but I am not worried about that as we never fill the sink/put the head in the sink.

Or is this more likely the cartridge since it affects the hot much more than the cold? If it's the cartridge, we may have to replace the whole faucet as the screw to open the handle seems to be stripped so it's not clear we'll be able to successfully get it open.

Thanks in advance for any suggestions!