With this being the trend, you're already more likely to leave what you called "daily driver" phone home, and only take the "important" one with you.
All the Google stuff is disabled, open source Contacts app,^1 no Google Play Services, no access to remote DNS, Netguard for application firewall and port forwarding, with computer I control as gateway. 1. Have yet to find any other app that can access contacts when storing them this way, even the Meta's biggest Trojans
Meanwhile, new phone, "important phone", stays offline. Wifi off. Location off. path?.xtracloud.net blocked. Phone is used for texting and phone calls, no internet access
The "banking app" argument, i.e., either install a custom ROM or give up or submit to surveillance, is a false dichotomy. There are other options
I don't use a phone for internet banking, I use a computer I can control; there is no "banking app" (talk about high risk, geez)
The "banking app" problem is a common refrain on HN but in the real world I know many people who do not use a phone for internet banking
Mobile OS just suck. It's like being forced to use MS Windows
It is the best answer at the moment. You can keep an absolute basic phone with all the banking and such apps loaded and nothing else. You treat it like an appliance. Your daily driver will be separate and can be running PostmarketOS or LineageOS etc.
There are several benefits off the top of my head:
1. Since you only install banking/govt type apps on your "important" phone, it stays more secure vs. putting your random game app along with the banking app on the same phone.
2. When you upgrade your daily driver, you don't need to deal with tons of re-auth steps for banking/govt apps.
3. Your daily driver can be customized to the nth degree because the pesky banking app won't be on it to refuse login because, say, you turned on developer options or rooted the phone.
4. You can even leave the basic phone at home for extra safety, if you wish, without affecting your daily driver.
5. You can root your daily driver and put as much adblocking setup as you want to boost your privacy. Your basic phone won't have enough activity outside banking/govt. to build much of a profile.