I can't speak for Slackware itself but Unraid is based on Slackware and has been very successful. I've been running it for several years now with few hiccups.
On slackware-current. Latest kde, mesa, fairly new lts kernel. All vanilla software (with security patches). Xfce, and more. No official gnome. Everything works, simple system. No official package dependency resolution, install a lot of packages recommended (they in groups). Good for me.
I have an intel arc 380 gpu, i know slackware current has preconfigured kernel. I havent tried building my own kernel but would it be easier using preconfigured or just build it?
I know intel arc requires 6.2 kernel as the driver and i believe mesa 22(or newer) .
Been a while since i built a kernel. Way i did it was (as root):
download from kernel.org into /usr/src/ (wget https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-6.4.3.tar.xz for example)
cd /usr/src/ and tar xvf the-downloaded-tarball
rm linux - it's a link to kernel source, so that programs can compile against the kernel (rarely necessary)
ln -s linux-downloaded-one linux - makes new link to downloaded kernel
cp linux-installed-kernel/.config linux/ - copy the old config to the new
cd linux then make oldconfig - a lot of questions about all the new options, that should include the new arc drivers if they are not included into old ones
make menuconfig or make nconfig - are TUI-s to configure the kernel. nconfig has a search (F8)
make bzImage modules - to compile the kernel and modules (basically shared libs)
make modules_install - copies modules to /lib/modules/version (important as most drivers are modules)
cp arch/x86_64/boot/bzImage /boot/vmlinuz-version - copy the kernel core to /boot
edit /etc/lilo.conf - if you use grub then idk
go to bottom, copy the whole block including image = ... , keep the original to have a bootable kernel
change /boot/vmlinuz to whatever i called mine
run lilo
reboot
reorder lilo boot order if i forgot to before, and lilo then reboot again to confirm
Not the official slackware way, but.. actually slack is the slackware way. Have borked my system plenty of times and had to dig up the install cd/usb to fix it.