OK - so you have 2 problems.
The realtek firmware is part of the install - it's already provided in the sparkylinux-5.12-x86_64-minimalgui.iso
If you do sudo apt search firmware-realtek
it should show firmware-realtek/stable,stable,now 20190114-2 all [installed]
Binary firmware for Realtek wired/wifi/BT adapters
You've replaced it with an external firmware package.
As part of that you have learned about the use of modprobe to get wifi firmware running.
If you did not use modprobe with the original installed firmware we do not know if it is a problem with that particular firmware, or if it just needed a modprobe kick to get it working in the first place.
Just to be on the safe side I would download the Debian firmware package so you have that locally.
Select the relevant mirror from https://packages.debian.org/buster/all/firmware-realtek/download
I would also grab the buster-backports version from https://packages.debian.org/buster-backports/all/firmware-realtek/download
- just in case.
The short way round is then to uninstall the github driver using the instructions on their page, then re-install the Debian firmware.
If you have an ethernet connection on the laptop you can just go to synaptic, find the firmware-realtek and just re-install.
If not then navigate to the download location - open terminal in the folder and sudo apt install ./firmware-realtek_20190114-2_all.deb
Reboot and see what happens. You may need to modprobe it once.
What I cannot see is whether the github firmware has left anything else behind that may cause problems. I also have no idea how that firmware would interact with your laptop in coming out of suspend. By the way, suspend and hibernate are 2 different processes.
If it does not work at all with the original firmware I would then install the backports version, reboot and see what happens.
If it still doesn't work I would just re-install and start again - I had this issue with Broadcom firmware on HP laptops around 10 years back with b43 and b44 firmware and if it got messed up it was just quicker to start again.
So, if you get the point where you have to re-install, just use modprobe after installation - with the stock firmware, if no go then use the backports firmware.
My guess is that it will work after reinstall and using modprobe to get it working first time.
Once all that is done, and you can get wifi connecting after reboot and shut down, then is the time to investigate the suspend issue (which is not uncommon).
The other possibility is that it may be related to Bluetooth. I am not sure with your machine but I do know earlier HP did use a combined bluetooth and wifi chip which could switch itself off. When you machine comes out of suspend have you used the wifi enable switch on the keyboard/body of the laptop? It may be worth investigating the rfkill utility - google it.