Money laundromats.
Atemu
It’s the best solution, but my phone doesn’t have a headphone jack (fuck you, Apple).
You can buy a tiny DAC that plugs into the digital port of the phone.
Cookie banners are not really about cookies.
What they're actually asking for is consent to process your data for profit in unethical ways. That usually involves cookies but could theoretically be done entirely without. They're just a technological standard.
You might aswell say: "We use https. [consent] [settings]"
Note that Android usually does a pretty good job of that by itself. Make sure you're not using (zram) swap or anything that would confuse Android's memory management.
If your RAM isn't >50% full, memory used by apps likely isn't the issue. Keep an eye on that.
In what ways? The worst it could do to the TPM directly is invalidate your secure boot unless I'm missing something.
it still leaves stuff around sometimes. I’ve seen it plenty.
You still haven't declared what this "stuff" is and, more importantly, where it leaves it.
App data folders left behind
What kind of "app data folders"? In /data/data/
? I doubt it.
downloaded files left behind
Duh. If the user downloaded files through the app and explicitly told the app to put those in downloads, those should remain. It's user data at that point, not app data.
Downloads are also just inane user files. They won't slow anything down (again, excluding excessive storage use; causing free space issues).
There’s quite a bit of stuff that builds up that app installers don’t remove.
Such as?
Because Android is still pretty open, the rules around this stuff aren’t as mature as say the Windows MSI database.
"Mature" and anything relating to the insanity that is Windows package management do not belong in the same sentence.
By default, Android has pretty strict guidelines where apps are even allowed to store state to begin with and will wipe all of those places upon uninstall. Integration state (default apps, app-related system settings etc.) is quite minimal and I've never had any remaining after an app has been uninstalled.
The only possible leftover state after uninstall I can think of is things apps can store in the user storage ("sdcard") when given explicit permission to do so.
Besides, app data storage of any sort is unlikely to "bog down" your phone anyways unless usage is abnormally excessive, making you run into IO or free space issues.
Not really. If you uninstalled all apps, you'd effectively end up in the same state as a clean install (modulo system settings). Reversely, if you did a clean wipe and then installed all of your apps again, you'd end up in roughly the same state as before.
In 9/10 cases, it's not the OS that's bogging down your device but the apps. Take a look at memory usage and uninstall or stop things you don't need running in the background.
Note that some SOHO router appliances block DNS responses with local addresses ("rebind protection"). You may have to explicitly allow-list your domain(s).
I don't know much about this space, so I'm not certain this kind of tool is what you're looking for but I know of https://penpot.app/.
You won't find FOSS.
There are alternatives to Google Pay on Android however. My bank (a "Sparkasse", German government-owned bank) has its own mobile payment app which appears to just simulate a Visa/Mastercard's NFC chip. IME it works pretty much on any terminal that accepts physical contactless cards.
Banks have much stricter privacy policies by law and I need to accept their terms anyways.