Just ran into this myself and super frustrated. I appreciate all the context and reasoning, but still making a tough call of either getting rid of Kagi for me, or finding a way to justify twice the cost at $10/mo in our budget right now. I'm under 300 searches a lot of the time, but it's too frustrating to stay on Starter and having to switch to another search service when I do go over.
I'm considering switching to Pro just for a month when I hit the limit, and then switching back, but that's definitely a pain. Gonna have to think on it a bit, I really do love Kagi and will miss it a lot if I leave. Just really struggling to get our budget back under control right now :/