Can you sudo dmesg | grep microcode and see if you have any errors?
If so, I’d be inclined to sudo dnf reinstall microcode_ctl then do a sudo dracut -f to regenerate the initramfs, and reboot. Be sure to have a working fallback kernel like LTS installed so you can recover if need be.
Edit: I just read you changed to Ubuntu. I can’t be arsed to figure out how Ubuntu does this stuff so that’s on you to figure out. Alternatively, install Arch and use intel-ucode package.