I am installing mobile apps with accrescent, f-droid and aurora on grapheneos. There is a handful of apps I have never been able to install, because they are regionally limited and you have no control on regional accounts that aurora accounts use. I just live without them, no big deal. The service is usually provided by a web page anyway.

I am using an external cloud storage with wasabi as secondary backup site, I don't need any other cloud storage.

I have a ten-year-old phone running Android 6 and use a seven-year-old version of K-9 Mail. I didn't expressly stop upgrading, but every time new hardware or software comes out, I compare features before upgrading. With a desktop computer running Linux or BSD, the hardware doesn't get worse, and the software rarely does, but it's easy to avoid the worse software, because it won't be the only option. With phones, both the hardware and software seems to have peeked in 2014, with newer versions being worse far more often than they are better. I've had to replace the battery in my phone a couple of times, and I've added more storage, but those updates only took a few seconds. My Note 4 has more features and a better screen than pretty much everything that came after, and with an unlocked bootloader, I could keep updating the kernel long after T-Mobile stopped releasing updates. (Although, the last update was more than six years after release.) Eventually the Kernel was too old to update, but by that point I was well into security-through-obscurity, by running a combination of Kernel and user space so obscure that nothing automated could gain access, even through known vulnerabilities.

I stopped updating K-9 mail when Google started interfering with notifications, to coerce developers into their Firebase hosted service. The old version, on an old version of Android, has 100% reliable notifications that are generated locally, when IMAP receives a push message. Also, I don't need to have my phone logged into a Google account, to receive IMAP messages, so I don't. This also means that there aren't any tokens saved on my phone that could compromise my gmail account, and I don't need to password protect my entire phone, just the email application. I also save my photos unencrypted to the microSD card, so if anything happens to the phone, they are easy to recover.

I only use Gmail, because I've had the address for over 20 years. I use Google Voice, so that I can read and send SMS messages from a computer, and can keep the same address even when switching phone lines. There's other providers that offer the same service for a few dollars a month, which I wouldn't mind paying, but every one I have looked into has requested I upload a copy of a photo ID, which is clearly a bad idea.

There are a few commercial applications that I run, and they work just fine on my phone. The only thing that I can't use natively any more is eBay, because it recently started requiring a Google account to use it, so now I just use the web page, which works equally well.

I never really used native banking applications on my phone, because banks tend to do very insecure things, like store highly-trusted tokens on the phone that are protected with low-security measures, like PINs or biometrics. Instead I use the web interface, which requires a password every time it is accessed.

When my phone was new, I used Google Pay instead of a physical credit card, for several months, but it was slow and hit and miss whether it would work, and I brought cash as a backup, which I quickly realized was even faster than the debit card I had been using before, and I wasn't at risk of credential leaks that would require I get a new card number, so after the whole experience, instead of switching from credit cards to NFC transactions, I ended up switching to cash, and as an added bonus gas is much cheaper, and several retailers I shop from often charge an extra 3% for card transactions, which I don't have to pay.

I've always carried portable electronic devices with me since the late 90's, from graphing calculators to PDAs and even a PSP, before I started carrying a smart phone. All of the most useful stuff then and now, like K-9 email client, Simon Tatham's puzzle collection, an HP-50g emulator, a 3rd-party YOuTube client, and random stuff from an audio spectrum analyzer to a WiFi spectrum analyzer are all open source, and on my phone I get them from the F-Droid market or download them directly from the developers web page or version control host. The only proprietary software I run often is Libby, a tool written by Rakutan that I use to access audiobooks from my local library, and it's just a wrapper over a web interface, so it works fine on Android 6.

Honestly, the difficulties from not following the tech industry playbook isn't specific to a phone. The biggest challenges I've faced were Reddit blocking thitd-party clients, at which point I stopped using Reddit, and now Cloudflare's capthca system is so agressive that I can't get past it without using a Chromium based web browser, which I refuse to do, so I stopped visiting several sites because of that.

Apps can be (side)loaded from elsewhere, IF one is using that appcrap on mobile at all.

Google didn't invent (Web)mail.

what on earth do you need google for?

No challenges at all.

There are better alternatives to google or any of the other big surveillance USA companies.

I sign in to all my accounts, Bank, pay my bills, Utility Companies, Government, Lemmy, mastodon, Nextcloud, Kdrive, everything, with protonmail or tuta mail.

I dont use amazon, I only use independent shops, so I sign in to their websites. I dont need google.

I dont do any social media. like Boatrace-crook, X, reddit, and the like, either.

My phone is Lineage so I only use F-droid, Droid-ify and neostore for apps.