simplify root partition size suggestion

archinstall/lib/interactions/disk_conf.py

@@ -238,21 +238,20 @@ def suggest_single_disk_layout(
 	if not filesystem_type:
 		filesystem_type = select_main_filesystem_format(advanced_options)
 
-	total_size_value = device.device_info.total_size.value
-	total_size_unit = device.device_info.total_size.unit
-
 	# root partition size processing
-	root_partition_size_gib = 20
-	if total_size_unit == disk.Unit.GiB:
-		if 51 > total_size_value // 10 > 19:
-			root_partition_size_gib = total_size_value // 10
-	elif total_size_unit == disk.Unit.TiB:
-		# maximum part size
+	total_device_size = device.device_info.total_size.convert(disk.Unit.GiB)
+	if total_device_size.value > 500:
+		# maximum size
 		root_partition_size_gib = 50
+	elif total_device_size.value < 100:
+		# minimum size
+		root_partition_size_gib = 20
+	else:
+		# 10% of total size
+		root_partition_size_gib = total_device_size.value // 10
 
 	sector_size = device.device_info.sector_size
 	min_size_to_allow_home_part = disk.Size(40, disk.Unit.GiB, sector_size)
-
 	root_partition_size = disk.Size(root_partition_size_gib, disk.Unit.GiB, sector_size)
 	using_subvolumes = False
 	using_home_partition = False