Rtkmips rtl8198c help

I couldn't use the official repo as it lacks support for rtkmips, but I found https://github.com/choryuidentify/openwrt_rtk/tree/ubuntu-20-04 which in turns is a fork of https://github.com/cgoder/openwrt_rtk to make it compile on Ubuntu 20.04.

That's OpenWrt 14.07. It's pretty old, nevertheless I'd like to keep it updated with security fixes and maybe new features, but I have no idea how to update it. The repository isn't updated in 5 years except for build fixes.

Did you contact (either of) its maintainer(s)?

rtl8198c has never been supported by OpenWrt and given the typical system specifications (2/8 or maybe 2/16) it's never going to be supported either. Check "lexra" as search term for further background information.