Kryonaut is noticeably lower in temps than the mx4. I would do the swap if it were me as I know the improvements, although slight, are still improvements that will be greatly appreciated and will help your situation out probably more than you realize.
Have you updated your hw info program to the latest version? I remember reading in the new version update release notes/change log about some changes or additions or something regarding GeForce RTX 2070, 80, 80ti ICX temperature reading sensors will be more accurate or something....
As for your cpu overheating... just food for thought, but I took some sandpaper to my 9700 and shaved about 5c just mindlessly (semi wet) sanding the top of the die for about 8-10 minutes.
I have my 9700k 5326mhz / 5026mhz cache with ring down bin disabled, and all power restrictions/current restrictions and limits set to max, stable at 1.35v LLC 6 (asus hero xi) while running some 3 year old g skill 4266mhz c19 Kit at c14-14-14-34 @ 3752mhz at command rate 1 at 1.45volts while all being air cooled using a noctua d15 lol.... (doesn’t pass 65c while playing counter strike for 5 hours and scores 100th percentile in every category except video card on userbenchmark)
Delided and replaced the lid with the rockitcool copper lid and yes that thing does work and does drop temps a couple of C at the very least, so if you are going to delid or lap your cpu or even change out the mx4, id visit the rockitcool website and get the copper lid there and replace the trash stock intel lid. Just my 2 cents, cheers and good luck