A lot of teams use us for their Gmail & Google calendar integrations.
If you want to run complex queries across large parts of the data, syncing + indexing on your side will be necessary. Limits on filters, pagination & rate limits make it infeasible to search across most of a user's inbox without tens of seconds to minutes of latency.
But before you sync all the data, I would test if your users actually need to run such queries.
Both Gmail & Google Calendar have a query endpoint that searches across many fields. I would start with a simple tool for your agent to run queries on that, and expand from there if necessary.
Both Nango and Composio could do this for you.
With Nango, you would also get syncs on the same platform, if it turns out you need them.
Hope this helps!