It’s quite common for an OS image to only be the size it requires to store the image in a file. That gets written to the SD car as it is, and the OS then resizes the partitions to fill the card when it boots up the first time. This is how it’s done on Raspberry Pi OSes. It’s possible that by booting your laptop from the SD card, that code did not run. But without seeing the info you are referencing to do your installation, we can’t be sure whether that is what’s going on. The screen cap you have provided does not show anything unusual in this respect. It is common for Windows to not be able to read most partitions and for there to be empty space on the SD card immediately after flashing it with a new image.
I’m curious as to why you want to avoid formatting the SD card. I do that every time before I flash a new image, just to make sure the SD card has no issues.
BalenaEtcher does not do anything to the SD card except overwrite it with whatever comes within the image file. If the SD card has other partitions on it before you flash, that usually gets cleared away, and the image replaces all data and partition info on the SD card. It is possible something preexisting on the SD card could trip up balenaEtcher, but those cases are few and far between. Reformatting the SD card with “SD Card Formatter” from the SD Association (https://www.sdcard.org/downloads/formatter/) can help you assure the card is completely clear of any existing data or partitions that might get in the way of an image flash.
If you go that route, make sure you select an “Overwrite” format, and if the option is available, check CHS format size adjustment. An overwrite format takes a while to complete, so be prepared for that. Even if you only do a Quick format, SD card formatter will remove existing partitions and data, But it doesn’t write to the entire SD card, and won’t find possible errors on the card.