I’m looking for more ideas in the practical level than pure support, and this is so wide question, I suppose, that defenetly feature request this isn’t. And answers like ”no can do, live with it” is totally valid too, if things are that way.
The issue is synonyms, but not limiting to that, but including different witing forms, that are by definition synonyms too. As an example: color vs colour. Actually that is an example from real world too. I was looking for one thing here some times ago, but I couldn’t find what I eas looking for, because I used colour instead of color. Using right form gave me answer right away.
We finns use synonyms, a lot. And top of that we have some differences, quite many actually, between book language and spoken language. The soup is ready because we have someting like 100+ dialects too, mixed with spoken finnish.
I know it is impossible to solve all conflicts, but I would really much like to find something. You know, in the level of color vs. colour.
At the moment most of the users don’t use searching. That is a globat question, and the root issue is searching has’t ever worked in any sites. Discourse’s solution is not superb, but it is better than many, I give that. It doesn’t suck totally. But still I quite often guide users to go via Google — yeah, I know, no one can’t bear Google, that is a fact too.
Actually searching, not problem solving, was the main reason why I put so much expectations on AI. But… it wasn’t improvement, but different way to get wrong hits 
Well, that’s true with OpenAI at least, and their models are all the time lazier and lazier (offering mostly just one hit because LLM is totally sure it is right, even it is totally wrong, and never more than 20, is just one part of that lazyness). But that is the situation here too, so I don’t know if self hosted, Google etc. would be a solution.
When I’m writing on my forum I have tendency to use different forms and synonyms. I works when I start a topic (something I do a lot), but I can’t get my users to adopt same thing. All I can do is tell to rely to tags and summaries, and just browsing. Or try use AI with exact prompting, what they don’t do more than once, because they practically never get what they were looking for.
But to keep things simply in the messed world: what would be the practise with color vs. colour situation, when just colo would give too many wrong hits like colon?