Ok, so people with power get together and probably talk about how to better wield that power. People who are in the financial business get together and talk about how to make better financial decisions... there are even laws against hedge funds sharing trading knowledge and all that (not my field so don't know the details here but this is easily searchable). Anyone that does networking in their field gets together with other people who practice or work in the same type of job, and talk about it and share ideas.

So just on that basic premise, people who have money and power, will absolutely conspire on how to get more money and more power. The real question is to what extent? But even without going there, it is not hard to see why the governments of the world have implemented the same solutions to the pandemic (as an example). There is something going on that they will not share with the public, and this is evident based on how they are synchronizing and promoting the same solutions (everywhere masks, lockdowns, vax, etc.).

Again, this isn't even going that deep into "theory", just accepting that people naturally conspire (a.k.a. network), and that this has happened because we can clearly see the same response globally. A non-conspiratorial world would look very different, with a much wider range of responses from each country, but instead we just see a few countries deviating (Sweden, Brazil, India) which of course get slandered or ignored by the media.

So in regards to the pandemic, it is not far-fetched to conclude that governments in Western countries are conspiring to control the public and using this virus as an excuse. That is the most basic "theory" I can think of. It doesn't require anything crazy, just acknowledging, the people at the "top" will network and do so to consolidate more power to then control people and get more money. It's simply corruption dressed as empathy.