Ok, I'd check. If you're not on BIOS version 1903 or newer, I'd update. 1903 is not security related, it's a performance update which often means compatibility or hardware improvements. Anyhow, even if it's not related, it's still a good idea.
So, AIO mount, outside of CPU, or anything else you can actually "touch", usually won't be hot, even if you have 110 degree core temps. Especially not if you have a heatsink or waterblock attached to sink off the heat.
Have you checked to see if the backplate or mounting hardware for the backplate to water block mount have become loose over time. I'd remove the waterblock, check that the backplate to mounting bracket fasteners and standoffs are all still very snug, without being overly tight, clean all the thermal paste off the CPU cooler and waterblock, add about a half of a pea sized blob dead center on the CPU lid, and then reinstall the water block making sure it is merely fully seated and snug. It does not need to be cranked down overly tight.
Another thing is, vibration can transfer through the tubing and make it feel as though water is traveling through it when the pump is actually not moving any fluid. It would be unusualy for two coolers to do the exact same thing though.
It might not be the worst idea to remove the CPU while you have the cooler off of it, and do a visual verification that there are no bent pins on the motherboard. You may need a magnification device like a magnifying glass or high powered reading glasses to see any discrepancies though. A slightly bent pin that causes no trouble at first could easily develop into a problem later on through vibration and movement of the unit later on, and a shorted pin could certainly cause temperature issues. Probably not, but always worth checking anytime something is "off" with the CPU.
Might also not be the worst idea to reset the BIOS to default settings and then enable the memory XMP profile again but make sure to NOT choose to enable the ASUS enhancements if it prompts you to do so. You want the default Intel CPU behavior, not the enhanced ASUS CPU profile. If you need to update the BIOS, I'd do that first and then do the reset afterwards. Updating does not always reset all BIOS settings.
BIOS Hard Reset procedure
Power off the unit, switch the PSU off and unplug the PSU cord from either the wall or the power supply.
Remove the motherboard CMOS battery for five minutes. In some cases it may be necessary to remove the graphics card to access the CMOS battery.
During that five minutes, press the power button on the case for 30 seconds. After the five minutes is up, reinstall the CMOS battery making sure to insert it with the correct side up just as it came out.
If you had to remove the graphics card you can now reinstall it, but remember to reconnect your power cables if there were any attached to it as well as your display cable.
Now, plug the power supply cable back in, switch the PSU back on and power up the system. It should display the POST screen and the options to enter CMOS/BIOS setup. Enter the bios setup program and reconfigure the boot settings for either the Windows boot manager or for legacy systems, the drive your OS is installed on if necessary.
Save settings and exit. If the system will POST and boot then you can move forward from there including going back into the bios and configuring any other custom settings you may need to configure such as Memory XMP profile settings, custom fan profile settings or other specific settings you may have previously had configured that were wiped out by resetting the CMOS.
In some cases it may be necessary when you go into the BIOS after a reset, to load the Optimal default or Default values and then save settings, to actually get the hardware tables to reset in the boot manager.
It is probably also worth mentioning that for anything that might require an attempt to DO a hard reset in the first place, it is a GOOD IDEA to try a different type of display as many systems will not work properly for some reason with displayport configurations. It is worth trying HDMI if you are having no display or lack of visual ability to enter the BIOS, or no signal messages.