The spd tab of cpu-z says it is still running at 1:1. Look at the dram and uncore frequency.
You don’t need to change this from auto.
Should be enough for reaching 6000 mt/s. Don’t go beyond 1.4 which is the expo voltage.
This could be just a GPU related issue. From personal experience with a rtx3070, I’ve seen that uefi is only visible when connecting to iGPU, even with a dGPU installed. Try connecting your monitor to dGPU when accessing uefi. This is not related to the post issue.
You should not have to override and relax the timings once you set expo. You can override (reduce) the frequency and voltage. Leave timings at auto with expo enabled.
This is fine as memory is retraining, should improve with memory context restore set to ON during subsequent boots (only if you don’t change any UEFI settings again).
Please don’t go beyond expo voltage as you most likely will damage your system.