The problem of higher LLC isn't necessarily your VRM getting hotter (although it will), it's that it feeds higher voltages.
LLC works to 'smooth' the vdroop you get, how much your voltage dips in the wavy up/down voltages always do (it's just electronics, your voltage is NEVER stable at a single voltage, despite your software saying so and how good your mobo and psu is, your motherboard actually just reports an average). However the less droop you have, the higher of a peak you have. So essentially LLC just raises your vcore, but it works to make your voltage more stable at the cost of increased voltage (+.27v Extreme/1.47v is about equal to +.34/1.54 High, about an additional .6v+ for Extreme over High LLC basically).
vDroop also keeps your CPU a lot cooler, by allowing it to dip much further, your chip stays very cool as the voltage can fluctuate a wide range. With higher LLC, your vcore is higher so therefore just that in and of itself is hotter, but forcing the voltage to run a more constant, higher voltage rather than naturally going up and down as necessary, really turns up the amount of voltage being fed to your chip and the heat. So even with similar vcore settings one LLC vs another, your peak and bottom voltages on a higher llc setting is much higher.
Higher voltages simply means higher voltages having to be processed by your VRM, meaning hotter VRMs. It's not so much LLC strains your VRM, but higher voltages - higher vcore strains the vcore VRM, higher vdimm strains the RAM VRM, etc. If you got a good VRM this isn't an issue, but on lower end boards your VRM's temps can be more of a limiting factor than your CPU temps. I'd say a 4+1 mediocre quality phase will struggle with higher voltages, ~1.35vcore (regardless of chip, it's 1.5v is 1.5v). 3+1 will struggle with anything above 1.3, really.
Like on my msi z77a-g41 and biostar a770e3 am3, VRM temps approached the max of low quality mosfets around 90*C way before my CPU temps became a concern. Good boards will have sensors for your VRM temps, not just for info but it's also used by the vrm computer to best allocate voltage amongst the phases, but it's always a good idea to place thermal diodes on your VRMs, especially if your board is so low quality that it doesn't tell you VRM temps.
I mean my Z77X-UD5H, I maxed out all the PWM and VRM settings, yet I never go above 60*C even with 1.55vcore. While 1.35v on my Z77A-G41 would push temps above 90*C on the VRM.
Now obviously asrock fudges voltages badly and asrock boards on z77 are questionable quality, but even high quality boards follow a very similar to pattern to the one in this video where voltages may be rising yet in software is shows no rise at all (the disparity between software read-out and DMM read-out has nothing to do with VRM quality, and everything to do with simply the equation the motherboard manufacturer uses to report voltage via software, which they often fudge so it seems like a certain motherboard is awesome because it require less vcore for the same overclock when in reality it uses the same).
VRM really shouldn't affect stability unless your VRM is getting hot (VRM performance will degrade at higher temps, how bad it degrades though depends on how bad the VRM is, better quality VRM can handle more heat, stays cooler, and has a higher max temp).
Be aware that the nuances of LLC on vcore will generally not be picked up by software voltage readings. It's very likely that even when your software is telling you your voltage is dropping a bit, that it's actually rising:
This has the potential to make it harder to achieve stability. I'm using a Medium LLC with no problems. I'm also using an Offset, and using Medium is allowing me to keep C3 and C6 enabled with no problems. Using Ultra High results idle lock-ups and BSODs until I disable C3 and C6. With C3 and C6 enabled, I enjoy a ~15W reduction in my idle power consumption.
Unless you have a digital multimeter to tell you what your voltage truly
is and you have stability tested to see what's the lowest voltage setting you can be stable on each LLC setting, I strongly recommend you just stick with the LLC setting recommended by every single person and guide and by people who have actually used a Digital multimeter and taken the time to see which LLC setting is best and stability tested to see which resulted in the lowest true voltage needed.
Like with High LLC, it appears I need 1.54v for 5ghz to be stable but in reality it's less than that, while Extreme LLC I can be stable on just 1.45v put in but in reality it's feeding my system 1.53v.
With any standard overclock, ie 4.5-5.1ghz, you should really be using Turbo LLC unless you used a DMM yourself to verify another setting is better. If Ultra high causes issues for you, that's probably because you aren't using enough voltage to go along with it. Your Vcore = VID + Offset + LLC. Just as increasing your offset increases vcore, changing your LLC will increase vcore too.
I mean you would be one in a million if you really were stable on less voltage on a lower LLC than the 2nd highest.
And where do you get the power consumption number? Software power read-outs are never accurate.