Title, I installed my system with two partitions, a big one and a small one for the OS. I figured 100GB would be enough for the OS one, but apparently not as it keeps filling up. Steam keeps filling it for some reason, something to do with Proton. I know that messing with partition sizes has a risk of data loss and all that, and I don’t really want to lose parts of my OS.
Probably not without LVM or an external drive to restore from. Depending on which partition comes first, you’ll either have to extend the OS partition “leftward” or lop off the front of the data partition, and there isn’t a good way to do either nondestructively.
If you have LVM set up, you could reduce the storage partition, make a partition in the new free space, and lump it into the volume group for the OS partition.