First of all, let me say thank you for your excellent project. I've been looking for a project like this for a long time and finally found this. It works fine with these steps on the RPi OS Buster which is available on the Raspberry Pi Imager as Raspberry Pi OS Lite (Legacy) and version of kernel is 5.10.103+.
But on the RPi OS Bullseye which is available as Raspberry Pi OS Lite (32-bit) and version of kernel is 5.15.84+, I got the below error:

Creating symlink /var/lib/dkms/rtl8188eu/5.15.84+/source ->
                 /usr/src/rtl8188eu-5.15.84+

DKMS: add completed.
Error! echo
Your kernel headers for kernel 5.15.84+ cannot be found at
/lib/modules/5.15.84+/build or /lib/modules/5.15.84+/source.
You can use the --kernelsourcedir option to tell DKMS where it's located.
rtl8188eu, 5.15.84+: added

The /lib/modules/ folder is as follows:

pi@raspberrypi:~/gc_setups $ ls /lib/modules
5.15.84+  5.15.84-v7+  5.15.84-v7l+  5.15.84-v8+  6.1.21+  6.1.21-v7+  6.1.21-v7l+

I can see there are unexpected folders for kernel version 6.1.21 created. Also, in the collect folder 5.15.84+ is as follows:

pi@raspberrypi:~/gc_setups $ ls /lib/modules/5.15.84+
kernel             modules.builtin            modules.builtin.modinfo  modules.devname  modules.symbols
modules.alias      modules.builtin.alias.bin  modules.dep              modules.order    modules.symbols.bin
modules.alias.bin  modules.builtin.bin        modules.dep.bin          modules.softdep

There was neither a build folder nor a source folder.

On the contrary, in the 6.1.21+, the build folder was created:

pi@raspberrypi:~/gc_setups $ ls /lib/modules/6.1.21+
build

I guess that as if the dkms is confusing as the kernel version of 5.15.84 and 6.1.21 but no idea why.

Do you have any suggestions on what I've missed steps or how I can fix it? Thank you for your kind help.