My Netflix account somehow was accessed again despite changing the password. Where am I going wrong?

For context, it started out with my Microsoft account. I got text messages saying that my account was accessed and didn't realize for how long this account was compromised. I quickly began changing passwords, kicked everyone out to my best ability, turned on 2FA etc.

Later it escalated to my email and thankfully because 2FA was already on, the "hacker" wasn't able to compromise to my email. They did the same on my iCloud account, they tried to access it but couldn't.

As for my Netflix, that was compromised long before my Microsoft account. I had customer service change the language and I reset my password. Somehow though they accessed that again cause when I logged in, somebody had created their own profile. I checked my laptop, desktop, and old iphone to see if maybe there was malware but when they were scanned nothing came up. Everything seemed clear.

I bought a laptop recently to reset all my stuff and noticed that it was telling me that Netlfix was leaked through a data breach. What exactly does that mean?

Also how do I check to see how my stuff was compromised? How do I check my iphone, laptop, and desktop?