I dont even want to think about how many partitions there are on my PC. windows has 4 or 5 just existing, then there’s root, home and swap plus 2 more for the 2 other drives. So… 9 or 10? its been a while since I had a reason to care.
As for what you should do, if you are replacing windows, it wont really matter what the format on the windows part is because youre going to need to back up the save data and reinstall those games eventually anyway. You cant really run the same game installs on both OSes.