AGR Not Closing: LMM Value Never Reaches Target

Hello everyone,

After noticing a gradual decrease in performance in my 1Z engine with 320,000 km and 66 kW, I compared the expected and actual values of the mass airflow sensor (MAF). -> I observed deviations of up to 300 mg per cycle.
Since I still have the old Pierburg mass airflow sensor, I soldered in a resistor as described in a technical article to correct the deviation. Now, in all cases, I'm getting a value that's almost 100mg/stroke higher. However, even at full throttle (more than 5000 RPM), the maximum value measured is only 690mg/stroke, instead of the expected 850mg/stroke. Before full throttle (around 3000 RPM), I'm getting a value that exceeds 800mg, which is well above the target value of 600mg.
Could it be that the EGR valve doesn't (properly) close at full throttle, which results in a lower need for fresh air, and therefore the MAF sensor measures less air?
Best regards,
Erwin.

P.S.:
The LMM (lambda measuring module) values seem to be correct, as can be seen in the MWB (measuring block), where the torque limitation determines the minimum injection quantity. The EGR (exhaust gas recirculation) system also doesn't appear to be clogged. (I checked the flexible pipe between the pressure sensor and the EGR pipe). I have added MWB 8, 9, and 11. I don't see any inconsistencies here, or am I mistaken?