I’ve been using Ecosia for a few months now and sadly that’s my experience too. For mainstream stuff it gives good results, but once I search for obscure phrases or god forbid another language, it often just completely gives up and doesn’t show a single result. It pains me to say that I more reliably get usable results from Google’s Web search (so with the AI crap removed) than from Ecosia with Google set as its results provider.