https://www.overclock.net/forum/6-intel-motherboards/1638955-z370-z390-vrm-discussion-thread.html
Your motherboard has a terrible VRM setup. I would suggest getting a decent Z390 board to maximise the overclocking potential of your 8700K and your RAM.
If your CPU isn't already delidded I would do that to drop 20C off the load temps. A delid tool and liquid metal is only $30-40.
Perhaps swap the fans on your AIO for Noctua A12x25, as they can maintain the same airflow at a lower noise level. $25 each.
Your case and power supply might also be worth upgrading, depends on what you have currently.