Migrating to cloud monitoring of all our devices and moving away from using collector server

You can't afaik if I understand the question. The cloud integration (LMCloud) with its LM-hosted cloud collector is rather limited compared to running your own collector. There is little overlap between what LMCloud would monitor for a VM vs what a you would be able to monitor using a collector server, except perhaps for generic cpu and network stats. You can do some customization of existing check types (like adding cloudwatch metrics) but it's nowhere as flexible as a collector server. LM doesn't let you run custom code on their servers (understandable) so the majority of DataSources does not run there.

Typically you still keep a collector server when using LMCloud so you get both cloud-based information (and non-server monitoring) but still have a collector server used to provide a more complete VM monitoring.

I suggest you start by setting up new cloud integration monitoring while still keeping the existing classic device monitoring in place. You can then see how it works and what data each can provide.

If you do keep a collector server around for LMCloud, I'm not aware of a way to transfer historical data between different devices. You may want to discuss that with LM support to see if it is possible (and let us know).