SD card wrong space

[z4v4l]

I'm guessing that what you're seeing is a 128 MB/121 MiB boot partition. It's likely that the main partition is using an ext4 filesystem, and as far as I know (I haven't used Windows for ~10 years) Microsoft has choosen not to support this filesystem (since support would make it easier for Linux-based and Windows-based computers to co-exist, which is of course a threat to MS.)

oh, jeez, I feel like you just solved some insidious plan of the Corporation of the Evil. a prose of the reality, that they don't support it because it's useless for the vast majority of their users. and writing a driver takes resources, wasting of which isn't wise - is not for fantasizers like you, right?

A better option might be to install and dual-boot linux on your PC and access both your SD card and your Windows NTFS file system from the Linux OS.

that would be a "better" option if one wants to destroy his/her NTFS volume and all the data it holds. for others, - just don't do that.

for the OP - after you flashed your SD card with the OS image for running on Pinephone, you should not use it elsewhere. and if you want it get back as a removable storage for your PC, you should reformat it - remember, according to the SDA specification, an SD card should be formatted with just one FAT volume and MBR partitioning scheme. so, having loads of non-FAT partitions with non-MBR partitioning scheme is already a risky thing (the card may not operate properly). but with SBCs and Pinephone, SD card is often a "harddrive", so we have no choice as of using it for flashing images, still better use eMMC for OS, if it's there and SD card a normal way.
In short, your card is fine, it's just "non-standard" formatted and it should not be used outside of the target device (Pinephone), unless you want reformat it.