Lenses are great but require an extra step often , if you remember to use them at all.
Have GPT/ some LLM set estimate the best lens for a query and then it is automatically set.
This could be a default as in the best case it saves time and in the worst case you have to change the lens and re-search which is what you have to do now anyways.
Obviously if I searched for PDFs 5 mins ago I orobably want more PDFs without being annoyingly overwritten. So after a lens is overwritten block the feature for an hour by default