Kyronaut will still perform better. Take a look at this charts:
https://www.tomshw.de/2018/09/10/innovation-cooling-ic-graphite-thermal-pad-im-test-bequemlichkeit-siegt-aber-was-ist-mit-der-performance/2/
sometimes spikes to 80-90c? That sounds bad...
Does it go back to lower temps after some time? Sounds to me like the is no water flowing at that moment, but that should be just increasing over time and not jumping to 90°C.
You need a lot of radiators. E.g. a single Mo-Ra3 420 with 200mm fans can give you water/air delta of ~5°C in games with high end hardware. To get even cooler you need a 2nd Mo-Ra3