im also on ITX but i have the 5800x it dose boost a little higher at stock.. but your CPU should be hitting 4.6Ghz out of the box so you have undervolted a little too hard and it not hitting max cloc.
if all you do is game, i can recommend ECO mode. all is dose is drop the TDP of the chip and if all you do is game this means it will run cooler and that it. you can then drop you curv offset
you could easy push 4.7 but the extra 100mhz is not worth it if you getting what you need and temps are good.
you need to install Ryzen master, this will show you the best 2 cores then back in PBO just let them have a little extra voltage.
thats a very good number, i have to use an offer set on my GPU and Liquid Metal.
no matter what i did i got a hotspot of 105c and some times it would hit 110c and force shout down, after i used Liquid Metal not my hot spot is max 80c in games and the gpu is at 70c
TBF the GPU is 10mm away from a glass panel. Liquid Metal saved the day