Would Google know if?

If you already have a domain on a business shared IP and if you moved it to a new host, would Google know that this domain was originally from it's previous IP?

I'm very cautions in regards to most of my money sites being on the same host and if I want to transfer 2 domains to a new host, would Google know that these 2 domains were on the previous IP or would they just see the IP that it's on once I move the domains to a new host?

I just want to make sure I'm not wasting my time. Otherwise I may have to buy new domains for my new host instead.

Of course it does. I had a PR7 blog back in the day, moved hosts and it dropped to PR3 and took quite a while to get above PR5. This was like 10 years ago, I know PR isn't a thing anymore.

That goes for CloudFlare as well? So I'm screwed if I'd want to transfer any domains to a new host since Google will know that those domains were on that previous host/IP?

Like if one domain gets penalized on the host, they can see the other domains on the host and penalize them too if they have the same/similar content? I guess I have to act like I'm starting over just incase if they do.

Even with cloudflare if you have anything on your site that calls back google such as analytics script, that will pass your ip.

google know's everything.. well not everything

I don't see a problem moving few sites to a new host if the IP is in the same country. As you said, your sites are hosted on a shared IP, there's usually around 300 websites on a single IP, even if Google knows these sites used to be hosted elsewhere, why should it bother about it, sites change hosts and IPs all the time.

Make sure the new host is faster than the old one, and you should be fine.