The log file you attached does not show a lot of thermal throttling. One of the reasons this happens is because Lenovo decided to lower the thermal throttling temperature. The Intel spec says that thermal throttling should begin at 100°C. Lenovo lowered this to 93°C. If you open the ThrottleStop Options window, on the right side there is a setting called PROCHOT Offset. Lenovo setting this to 7 is what causes premature throttling. If you do not see a yellow lock icon near this setting, you can lower the PROCHOT Offset value to increase the thermal throttling temperature. This will give you a little more headroom before throttling begins. Setting this to 2 or 3 might be a better compromise. If you are happy with the reduced throttling temperature then leave this setting as is.
The CPU P and E cache voltages do not have to be set equal to each other. Have you tried going a little further with the P cache offset undervolt? Some users are still stable beyond -51.8 mV.
There is not much else you can do without improved cooling.
To reduce EDP throttling, you can try increasing IccMax for both the core and the P cache. You can also increase Power Limit 4 or just set this to a value of 0 to disable it. EDP OTHER lighting up red under the RING column is normal whenever there is power limit or thermal throttling happening under the CORE column of Limit Reasons.