I'll take you at your word the arm is properly configured. There are parameters other than VTF and VTA. Some you can control and other are set when the arm is attached to the plinth.
However, two issues. First, a pivoted tonearm scribes an arc across a record. That means you can only achieve a good average for being perpendicular to the groove. At most spots on the record, you're going to be slightly off. Change a setting to perfect that for one spot, and then you're off at others.
Second, since the diameter of the record decreases as move toward the record's label area, the spiral of the groove's arc tightens. That inherently increases distortion.
One problem could be that a record may have subtle permanent damage from prior playing. If that's the case, you may be stuck with the distortion. However, I would expect that condition to vary quite a bit from record to record in your collection.
While inner grooves inherently have more issues than the outer ones, that shouldn't automatically mean audible problems. If every record has the problem, I think you're back to a setup issue. You might try rechecking if the distance from the pivot point to the stylus is correct, and also double check to make sure your cartridge doesn't yaw to the left or right. Also double check the anti-skate setting. The centrifugal force increases as the spiral tightens.
Good luck!
However, two issues. First, a pivoted tonearm scribes an arc across a record. That means you can only achieve a good average for being perpendicular to the groove. At most spots on the record, you're going to be slightly off. Change a setting to perfect that for one spot, and then you're off at others.
Second, since the diameter of the record decreases as move toward the record's label area, the spiral of the groove's arc tightens. That inherently increases distortion.
One problem could be that a record may have subtle permanent damage from prior playing. If that's the case, you may be stuck with the distortion. However, I would expect that condition to vary quite a bit from record to record in your collection.
While inner grooves inherently have more issues than the outer ones, that shouldn't automatically mean audible problems. If every record has the problem, I think you're back to a setup issue. You might try rechecking if the distance from the pivot point to the stylus is correct, and also double check to make sure your cartridge doesn't yaw to the left or right. Also double check the anti-skate setting. The centrifugal force increases as the spiral tightens.
Good luck!