That's not the question that needs to be answered, first you must allocate enough space for you system partition, and whatever other system related partitions that you want to use, var, temp, swap, you get the gist, then whatever space you have left is your home partition. This scenario being a default personal use desktop ofc.
If this is going to be a BTRFS system then it also doesn't matter since sub volumes share the total space available dynamically.
Also if this is a modern hardware consider not having a swap partition and instead use ZRAM.
It's fine. "Only 27GB" is hardly too small for the system, even a bloated system wouldn't take that much space.
But if you must have a larger partition I think a reinstall would be easier, resize the partition is possible but because of the encryption not a straight forward thing. I wouldn't bother really.