> So what are the alternatives here?
You have to be willing to live with something less feature-rich than what you can get on the latest iPhone 27 Max Pro(TM). And you have to be gutsy enough to click an "Install some other OS" button in your web browser with your phone plugged into a USB port.
Then to extend to services, a lot of it depends on your ability to deploy your own stuff. This can involve a lot of time reading how-to guides after you've installed Linux on a machine in your house. Given how much documentation is readily available online most people with a high school diploma can probably figure it all out, but you have to be motivated enough to refuse to be helpless.
Today you can purchase a Pixel 7[|a|Pro] and flash GrapheneOS on it. There's a lot you can get from F-Droid, but if you really want Google Play Store apps, GrapheneOS does a reasonable job sandboxing it. Create a new Google account just for that installation of Google Play Store.
Never sign into anything Google, Microsoft, Apple, Facebook, Twitter/X, LinkedIn, or whatever from your phone. Or at least if you absolutely have to, use a trusted web browser in Incognito or Private Browsing Mode.
Keep location tracking disabled for everything but your favorite maps app. Put your phone in Airplane Mode when you're traveling if you don't want cell towers to capture your location info. GPS reception still works.
WG Tunnel can get you to your server when you're not on your home network. Some people swear by Tailscale, but you have to trust them with your node info.
Syncthing works for backup for a lot of people.
For private maps I've been using Organic Maps with some success. Searching for places isn't necessarily trivial, but the navigation feature has always worked well for me.
For private comms you really need it to go both ways (you and the recipient). The weak point is likely to be the recipient's environment, but at least something like Signal gives you a chance.
Something like Fastmail works for email and calendar, since they're probably not building a profile on you and selling that to advertisers. DAVx5 is free from F-Droid for calendar sync.
Kagi works really well for search. Also, they probably haven't sold out to advertisers. DuckDuckGo is another option with another set of trade-offs.
For music you can serve FLAC files via minidlnad to VLC. minidlnad was a 3-minute tweak to a config file after I apt-got it. There are tons of options here.
Explore F-Droid for stuff that might do better for privacy, like Spotube, FreeOTP, Podverse, Librara FD, Cheogram, etc. I'm not claiming that the F-Droid apps will all give you perfect privacy, but in general they're probably better than a lot of the stuff that's pushed in the Play store.
Check out e-books and audiobooks from your local library. Or copy them to your device via Syncthing after feeding your e-books through Calibre's DeDRM extension. The idea is to keep from having to context license servers from your phone.
Give up on Apple or Google Pay, credit cards, and loyalty programs if you don't want your eReceipts collected and added to your consumer profile by companies that do that sort of thing.
None of this is a surefire way to give yourself perfect privacy, but it can greatly reduce the amount of your personal information that your government and/or corporations collect on you via your mobile device.