Good idea or bad idea to switch to GOS from stock for me? (Low threat model)

Designed1668 GrapheneOS is always a good idea. You won't sacrifice anything in most cases, only upgrade your security.

Is Google secretly recording me in secret? Does turning off microphone and camera do anything to stop this if this is happening?

They are not doing that.

Is Google able to see what I'm doing in other apps, like websites I visit in Brave and messages I send in Signal/WhatsApp?

Well, its complicated. They might get general usage stats but not exactly what you're doing. In some cases they would be able to read your notification feed, because they are responsible for delivering them. Signal protects against this, but idk about whatsapp.

Is Google able to see what I type and what I speak despite already switching to FUTO Keyboard/Voice?

Outside of their own apps, no. Ofc inside those what you type is up to them to handle.

Can Google see my passwords stored in Bitwarden?

They could theoretically and technically do many of the things you ask, but the real question is that, are they actually doing it? They are not looking through your passwords.

Can Google see what I have in my clipboard?

Possibly. Foreground apps can always read your clipboard which displays a notification normally. Idk how Play Services interacts with the clipboard. I doubt they are reading it actively though.

Is Google listening to my conversations (both in E2EE apps and regular calls)?

Calls through other services than Google is up to those to handle. They are not wiretapping you, no.

Does Google know what files I have stored locally?

Tricky to answer. They have access to your device, and they COULD read your file tree. But again, if you don't explicitly open a file with one of their apps, its very unlikely that they collect any of your own files.

Can Google read a PDF file I have stored on my phone?

They can. But they wont.

Am I infecting my PC with Google spyware when I plug my phone into it?

No, and your PC is 1000x more likey to contain spyware.

Does Google know which apps I have installed even when I install them from outside the Play Store?

Yeah, partially because of PlayProtect. They probably still know if you disable it. FYI every app on ypur phone has access to your installed apps' names. This will be patched in Graphene eventually.

Google "spies" on people with consent mostly. Not in unexpected ways, like some chinese OEMs or Samsung does.

If you have a problem with their ability to do nasty things, then yeah Graphene is certainly for you. Its also important to focus on what they are actually doing, to not go crazy :)

I have been using google messages with RCS on GrapheneOS without issue.

I would highly recommend trying Graphene, and setting up your phone as you best see fit for your use.

Designed1668 For example, I still plan to use Find My Device, Google Maps, Google Photos, Google Voice, and Google Messages (RCS).

I think only FMD might be problematic (never tried myself, you can search the forum), all the rest is fine.

Designed1668 Is Google secretly recording me in secret?

Yes. All, your voice searches are recorded as per the privacy policy and can be found in history.google.com. Besides that, some quick search returns results such as So Google Records All The Microphone Audio All The Time, After All?

Now, remember that the data Google uses and keeps for it's commercial activities is sort of bound by their privacy policy. The stuff they send you the government (search for "PRISM") is not. It's governed by Patriot Act and likely some secret FISA court's ruling. So what do their closed-source apps do? You never know. AOSP (Android) is open source, but there's a lot of closed-source crap that runs on top of it in Pixel OS and also in the OSs that run in phones by Samsung, Motorola, etc.

Designed1668 Is Google able to see what I'm doing in other apps, like websites I visit in Brave and messages I send in Signal/WhatsApp?

Yes. All notifications that come via GPS push (messages, email, online stuff) are known by Google, recorded by them, sent to Prism and even shared with local police without even being asked for warrants.
Local notifications (Brave's finished downloads) don't go through Google's servers.
In the middle you have services that encrypt notifications, like Signal or Proton. Google can't read those, but knows what services sent you notifications and when (which can be used in investigations to know who you're talking to, for example)

Technically it can also take screenshots of all you do in stock OS because GPS (Google Play Services) runs with a lot of privileges. If they do it or not, it's again up to you to speculate.
My own speculation is that they don't waste much resources on people like us, who are not of interest. But I wouldn't rule out that they start paying attention to you when you mention certain topics (I bet "ok Google" is not the only phrase that wakes up the voice recognition for example)

Designed1668 Can Google see my passwords stored in Bitwarden?

They definitely CAN. GBoard can read what you type, and pasting a password from BW is basically typing. Notice this applies to GOS too, if you use Gboard with network permission (or in a profile with GPS).
Also, it uses the clipboard, so GPS can read that too.

Designed1668 Is Google listening to my conversations (both in E2EE apps and regular calls)?
Does Google know what files I have stored locally? Can Google read a PDF file I have stored on my phone?

Same here. They probably can, they probably aren't.

Designed1668 Am I infecting my PC with Google spyware when I plug my phone into it?

Don't think so.

Designed1668 Does Google know which apps I have installed even when I install them from outside the Play Store?

Not only Google but every single app that you install. You know all those closed-source apps that are free? One of the things they're monetizing is this. GOS doesn't protect you from this either, yet. There is a project to limit app communication but it's not marked as a priority in Github.

Rizzler idk about whatsapp

Funny story. WhatsApp gives all your chat history and all your sent/received files to Google anyway. They push you to back it all up in Google Drive, but not to set a password. It's possible though and you should definitely go to the app's settings and ask to encrypt your backup. Or disable it altogether.

Rizzler FYI every app on ypur phone has access to your installed apps' names. This will be patched in Graphene eventually.

this is profile limited though isn't it? I hope

I wouldn't pretend that I understand what information Google can/does track from you. All I can say is you'd be giving them much less data after switching to GrapheneOS.
As for the apps you want to use, we all are ready to a different combination of privacy, security and convenience. You might choose to keep on using highly intrusive Google apps, such as GMaps or switch to a privacy-respectful alternative such as Organic Maps. The same applies to Findmydevice.

Eirikr70 Well, we can reliably tell what data they can access. On the other hand, there has to be proof if they are doing something suspicious.