Sorry I didn't see this post. Went through a period where I was rather distracted. The initial problem with search when we moved domains was that the Google search was not searching the Sims 4 domain at all, which meant it couldn't search either Forum. I think that everything is working well with that now. Guide results will normally appear first, although you could put forum in the search to help boost those results. To get more specific, site:carls-sims-4-guide.com/forum/ would deliver only results from the Forum. That is a good tip for anyone who doesn't know that you can search entire websites or sections of them that way.
The Forum's search, which appears in the top bar to the right of Sims 3/Sims 4/Help should have been working well all along. The limitation there is that you can't put Sims "4" since the 4 needs to be two characters. If you really really need to limit a search to the Sims 4, you have to use the filter at the bottom of that page, then select the boards you want to search from there.
Overall, I prefer the google search. It's much more up to date these days, and lets you specify Sims 4. I do not endorse it just because it's a feature that does earn some change, because it only earns some change lol. It's just better search overall IMO, although sometimes it can be a bit behind. Naturally Google's search algorithm is much better than the built in SMF search.