Hey Joshua!
You can take Humanitec’s reference architecture and exchange the symbols that you don’t like for others - see
https://humanitec.com/reference-architectures. Why those, if they’re not fully OSS you ask? Simple - you can grab the whitepaper or view the PlatformCon talks that explain all of the boxes - planes or capabilities - you don’t get that in the tooling landscape. But… for inspiration on what other products make sense in the spots, the landscape is great! Have a look here:
https://platformengineering.org/platform-tooling
If you have any questions - poke me for a virtual coffee together!