I had the same issue. It seems to work normally for me now, but I'm gonna test it out in a few more games to be certain.
Here's what I did so far:
Update all Drivers
Update BIOS to the newest version
Update EC to the newest version
Run Hextech Repair Tool to completely reinstall the game
None of this helped, until I found that during the freezes, my CPU load was exceptionally high. The culprit was a program called Nahimic. I think its some kind of audio driver. As the game went on, it used up more and more CPU load, until everything became unplayable. The process that did this was called "nahimicSvc32.exe".
So, I uninstalled Nahimic as completely as I could, ran CCleaner, restarted my Laptop and then found some cmd commands to help me write a quick batch script for closing any Nahimic processes that may be left.
To do that, open an empty notepad file and write the following:
echo on
title LIVE setup: spring cleaning
echo echo Live SETUP
echo
echo Killing nasty processes
echo
taskkill /f /im "NahimicService.exe"
taskkill /f /im "NahimicSvc32.exe"
taskkill /f /im "NahimicSvc64.exe"
taskkill /f /im "MSIService.exe"
taskkill /f /im "AGSService.exe"
taskkill /f /im "ShareX.exe"
pause
Save the file, remove the .txt and put .bat instead. Run that as administrator. I let that run every now and then, just to be sure.
Just played a game and it was the first in like 4 days without any issues. Hope that helps someone else, since it took me like 3 days to figure all this out.