Post:
/sbin/modprobe -c | grep -i "10ec.*8125"
to see, if your card is supported.
Leap is using a kernel 5.3.
But openSUSE is using a backported kernel from 5.8 or 5.9, so the above command shows if the kernel supports the card.
You can get the original Realtek driver in my Repo (after building):
zypper ar -f https://download.opensuse.org/repositories/home:/Sauerland:/hardware/openSUSE_Leap_15.3/ Sauerland
zypper in r8125-kmp-default