I use quarto: https://quarto.org/
The big thing I like is that it has fulltext local search, built in and easy to enable.
Search is possible on hugo, but it's not built in, you have to get a plugin, etc etc. Same for many other options you mentioned.
Heres my website: https://moonpiedumplings.github.io/
I mentioned an alternative to the what these websites do, using a package manager to install these instead of their bash scripts.
Both of the bash scripts you mentioned as an example are being used to install software. If you have examples of bash scripts that do things other than install software, then it's worth discussing how to handle those.
However, the reason why bash is so popular for usecases like configuration scripts or an Arch install script though, is because no other software besides wget/curl and bash is required to get it. Having to get an extra tool on the Arch install iso just to run an install script in bash, or to run a script that installs tools on a fresh, clean install, somewhat defeats the point of the script being written in bash imo.
Bash is inherently insecure. I consider security not just issues with malice, but also footguns like the steam issues mentioned above. Centralizing all the bash scripts to a "repo" doesn't fix the issues with arbitrary bash scripts.
And if you are concerned about malice, then the bash scripts almost always download a binary that does further arbitrary code execution and cannot be audited. What's the difference between a bash script from the developers website and a binary from the developers website?