Don't use AUTO setting for VCCIO / SA, With your RAM at DDR4 4266 it will set a very high voltage. Try with VCCIO 1.15 / VCCSA 1.20 if crashes 1.20/1.25. LCC is too high in my opinion try with LCC5, very high LCC increases temperatures.
Is up too you but I don't see a reason to leave the processor with manual voltage and locked to 5.3Ghz all the time. You can try this if you want. it will reduce slightly the temperature in partial loads and the power consumption at IDLE.
>SVID Beheivor: Best Case
>LCC5 o 6 max
>Voltage Adaptive > start with 1.26 but you will have to play with this value. With Adaptive the voltage behaves a little weird some times but is just a matter of trying and get a the right value. Control the Voltages and temps with HWINFO64
>AVX Offset - Personally i'm not a fan of AVX offset. But if processor can run 5.2Ghz AVX but crashes at 5.3Ghz, you can try negative -1
For stressing you can use HWBOT X265 / OCCT or since you have a 2080 Ti play Battlefield 5 that games uses AVX and is VERY cpu intensive and also sensible to unstable O.C. AIDA64 is too "light" in my opinion
Ryzen 9 3900X/2X16GB DDR4-3733@CL16/X570-I AORUS/RTX 2080 GAMING OC/IN-WIN 301/EVGA 850W
Heatkiller REV3.0+DIY AM4 Adapter/1X120+1x240mm/DDC3.25+EK DDC Res