Modifications of vendor image on Android 10

There is a vendor image in my device I want to change (unpack/mount, doing changes, pack/umount). My purpose is to update boot.img with my new kernel (in a rooted device). Unfortunately, it does not work due to incompatible versions between a newly compiled kernel (my compilation) to the previous kernel modules stored in vendor.img. As I figure it, I need to update the old ko executables stored in vendor.img in my product. The first step is to do dd from my device and adb pull it out to my build environment. While I tried to do a mount on vendor.img, I discovered it not working due share_blocks attribute blocking it to mount as RW (dmesg wrote: "...unsupported optional features (4000)"), To solve it, running the following command e2fsck -y -E unshare_blocks vendor.img will disable the share_blocks feature that prevented me to do mount as RW. Of course, doing mount RW works correctly. In the last phase, I tried to replace files in the vendor filesystem and then I discovered another challenge into my way, Unfortunately, there was a problem with limited space in the file system, For example: In case I want to replace the kernel module called abc.ko, deleting the file doesn't show any new free space in the file system. At this point, I can't update the old kernel modules with the new ones (compatible with the newly compiled kernel). Of course, running df -h . returned no free space and 100% used. Does anyone have any idea what I need to do?