iCloud - you don't really need an alternative.

Microsoft - You have many alternatives to Microsoft software. Linux, Libre Office, Java, Python, IntelliJ, ... pick one, or more.

Amazon - there are so many other stores. And cloud providers if you are into that.

Netflix - just another streaming service. You can decide how to consume media in many different ways.

Google - Mail you can host anywhere, it's not like Gmail is special. Online productivity suites are not that rare as once. If you insist on Youtube you can use it without an account, Android with fake account.

If you find yourself you can't switch, you are into much bigger trouble. It's ok to be burned once, but next time you start you new SaaS startup, think twice do you want to depend on specific company for all your needs.

Out of those I only have Google, even though I use it only for spam e-mails these days, having opted for Protonmail for the real stuff. The only reason I still have a Google Account is that my Pinephone Pro hasn't arrived yet. Once I get it and figure out it fills my most critical needs, the Google account gets shredded too.

Giving up on Netflix and Spotify was much less difficult than expected.

It really is that easy.