I eventually settled on Gemini 2.5 Flash Lite as my workhorse, using it against structured data/vectors as a chatbot. It was cheap, good enough, and most importantly, fast - but it's now being sunset and I'm not sure where to go to find similar performance.
Groq seems promising but developer access hasn't been available for months. I'd love to use open source, but I never found anything comparable (cost/performance/speed).
Would love to hear your suggestions.