Email: The most important component here is owning your domain. Then you can switch between providers. I'm using iCloud now because I can have email addresses for the whole family for very cheap and it integrates well with my Apple devices.
Search: Kagi.
Maps: I still use Google maps. The alternatives are just not as good here in Denmark.
Phone: iOS. I really want to try GrapheneOS but our government uses a national ID app which only works on official Android and iOS builds. It's very annoying to function without that app.
YouTube: Still use it as well, but with ad and sponsor blocks on computer and mobile. I have an Apple developer account and sign my own sideloaded YouTube apps.
Cloud storage: I switched to iCloud, but I keep a full local copy of everything in case I lose access to my account. I also built a home NAS and keep the movies on that. Basically anything which I don't mind losing so much.
Docs: I use Office applications primarily now instead of Google Docs.
I recently acquired my own domain, and perhaps that is a good idea, especially considering I can set it up on Proton too.
For Maps I tried HERE and TomTom, but they simply are not good enough where I live (in Europe, ironically). HERE doesn't know that some streets exist on my town, TomTom is missing a lot of addresses which makes things very cumbersome super quickly.
Phone: Apple is not an option. I despise Apple products, and I don't think they are any better than Google.
Cloud storage: I've switched to self hosting + tailscale here. It has been working actually pretty well.
Docs: I use Libre Office. Google Docs is shit.
Some bits are harder than others.
Most of my important email was migrated to a Protonmail account. With the exception with a couple of things tied to government services that don't have a path of changing your email, which sucks.
Android: Next time I switch devices I am going for GrapheneOS. Technically still an Android, sandboxed Google services and all, but a step in a better direction.
Android Auto/Waze: There's no competition here, sadly.
YouTube: Another thing that is very difficult to replace beyond just reducing my YouTube usage. I can use stuff as Newpipe or self host Invidious, but technically it is still YouTube.