Expert WordPress Migration

I am looking for a Wordpress migration expert.
We have websites across:
- 3 hostgator accounts
- 1 dreamhost account
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I need to move the sites all to a new dreamhost server that we have.
The other issue is, there are some sites that may have conflicts. E.g, we may have an old site that we have on hostgator, that someone rebuilt a on dreamhost but it already exists. So we need to also outline what those are, show me the old and new versions and go from there.
We need this to be a fast and secure transaction.
We also need all the sites to be added to cloudflare too and then added to digitalocean via runcloud and have a no downtime movement of everything.
Must be secure.
There are between 50-100 websites to migrate also.