Github Gists are good. They are discoverable, can be made private or public. They can be forked, stared and linked too.
I've also been publishing "emerging tech" snippets on my blog. They appear on a carousel on the bottom of the home page. This is good to showcase expertise in a particular language or framework.
I can recommend Cockpit CMS if you want to build your own selfhosted knowledge base. Here is a great tutorial to get started: https://willbrowning.me/category/cockpit/
I don't. Do people do this regularly?
Obsidian (https://obsidian.md/) might help you with that. It uses Markdown and you can tag your coding snippets and make a knowledge graph (https://en.wikipedia.org/wiki/Knowledge_graph) out of it.