If you really want to go for attempting the current one, I have a suggestion that should work on Windows. (if you have access to OS X natively, look at next bit of this)
It will be quite a lot of work, but if you get it working it will be great.
First, set up QEMU System PPC on the Windows computer to run Mac OS 9.2.2, (see
https://www.emaculation.com/doku.php/ppc-osx-on-qemu-for-windows). Install Mac OS 9.2.2 on the image file you make. Keep this image file. (not the ISO, but the one you installed 9.2.2 on with qemu)
Now use VMWare Workstation to install a copy of Leopard Server (iso:
https://drive.google.com/file/d/101HcsqgwYZrI6Fup-mCkiF_ur5f2MG5m/view?usp=sharing). Use XSVR-105-000-R-LN7-HGS-DPD-H24-8DH-LGQ-3 when asked for 10.5 server serial key. Once installed, grab a USB stick, or even better get the drive from the g4 and plug it into your Windows machine. I will refer to which ever you chose, as "the drive" Use the menu at the top to pass the drive connection directly to the VM. Also in the VM settings, attach the QEMU image (with the installed 9.2.2 on), as a hard disk (or other storage device) to the VM. Open up the terminal in the VM and...
diskutil list
diskutil unmountDisk /dev/diskX
or
diskutil umount /dev/diskX
(X being the disk of the qemu image attached to the VM)
diskutil list
diskutil unmountDisk /dev/diskY
or
diskutil umount /dev/diskY
(Y being the disk of the physical drive passed through to the VM)
sudo dd if=/dev/diskX of=/dev/diskY
(Use ctrl+t, to see how many bytes transferred, can take a while)
If all that works, now shut down the VM, and put the drive back in the G4 and see if it boots from it. If you restored the qemu image to a USB stick, try boot that the same way.
Obviously if you have access to OS X somehow, just use Qemu for OS X to make the OS 9.2.2 image, then restore that to the drive or USB stick by doing:
hdid -nomount /Path/to/qemu.img
(Take note of the number /dev/diskX, what ever X is)
diskutil list
diskutil unmountDisk /dev/diskY
or
diskutil umount /dev/diskY
(Y being the disk of the USB/Drive)
sudo dd if=/dev/diskX of=/dev/diskY
(Use ctrl+t, to see how many bytes transferred, can take a while)
and try boot the G4.