If we assume I will stick with the 4.5GHz, is there a safer way to do it than manual 1.335v with LLC on Ultra?
I'm not an expert on the subject but I try to avoid using LLC at all. I like the offset voltage way as I don't have to feed more voltages at idle and it helps to keep the overshoot voltage inline < Using high LLC can cause momentary high voltage spikes when the chip goes from load to no load to little load etc,
If it was me I'd just go into bios and save your current profile as it's stable. It's under the tools option I believe > overclock profiles or something like that. It's easyier to change up if you name them also.
Once you save the profile then try the offset voltage mode again. You just need to find the correct value to get you back to the same loaded voltage and you should be stable. Sometimes you'll be stable at a little lower vcore without LLC enabled at all. You gotta just play around with it. It's best to keep the LLC as low as possible but it's up to you if you wanna use it.
Try offset mode with a + value of 0.080v's or so and load it and see what your vcore is with the 45x multiplier. If it's higher or lower than you need just up or down the offset to get it closer. Depending on what your testing with the vcore will go up and down with the load.
It's trial and error with offset but once you get the hang of it I think it works the best. It's the way the chip was meant to be run so it shouldn't be too much work to get it to what your chip needs to be stable at a set clock.