Dang thats not very efficient.
Radiator as an intake places more heat in your case and with that set at the bottom of the case heat follows physics so you got hot air blowing into your case across all the components you want to stay cool. If a internal fluid cooler takes up to much space then a better option would be to look into the high end air coolers.
Like Cooler Master Noctua MSI Corsair Zalman or Thermaltake. You would want a dual 120mm to 140mm 4 to 6 Heatpipe device with a TDP rating of 200 to 250 watts. TDP is a measure of cooling effectiveness of CPU coolers compared to the CPU's normal power draw.
For instance I'm running a Ryzen 7 2700x 8 core at 4.2GHz base clock 3.7. With an MSI FROZR L dual 120mm fan cooler. Idle temps or in the upper 20'sC Load is around 51C.
Send what tower you built your rig in pictures would be helpful to.
I don't use fluid cooling but many in this community do with detail hardware specs we should be able to help you solve this thermal issue.
