Hard to say with 100% certainty, very complicated topic…
But i’d say if you want mainstream phone Pixel 7 + GrapheneOS is one of the best options, outside of full Linux phones with FOSS hardware / software or something like that.
You can significantly harden it by completely disabling all modems, bluetooth and usual stack, and only using it through wi-fi, to avoid all the nasty NSA stuff that is triggered via mobile network or SMS (in case if that’s your possible attack vector).
Yes, it could happen that way. However, that would not be end-to-end encryption. End-to-end encryption does not mean the message is encrypted only when it is sent or in transit. It means that nothing can interfere with it or decode it. Only the users involved in the message have access. Not even the platform itself has access to the message if it is encrypted end-to-end.
If the platform has access to the message prior to encrypting it, it isn’t end-to-end encryption. It is just encryption.
I understand exactly end to end encryption. But if they want some way of scanning the message so criminal activity isn’t being hidden there aren’t many options. I don’t look at it as breaking the encryption because it isn’t encrypted yet and hasn’t been sent either. I don’t see any difference of it getting scanned after it is sent if it gets flagged by either the sender or the receiver. If it’s criminal activity the sender or receiver sure isn’t going to flag it to have it scanned. I don’t know what the answers is. I just have an opinion right or wrong or indifferent. I feel something needs to be done so that there are more protections and the platforms are being held be responsible for what happens on their platforms. The internet is not the lawless wild wild west. It is a tool to be used responsibly for a purpose.
Look, it either is end-to-end encrypted or it isn’t.
You can’t have it both ways. If they scan the message before it is encrypted, that’s not end-to-end encrypted. End of story. 
I understand that it’s not when before it’s scanned but it is once it’s encrypted and sent.
I know that guy.
Lets just give up on this. I have my opinion.
Edit: I was replying to @dalto not ALL of you! 
Really?
Can you repeat it again please, i think someone could still miss it.
P.S. I’ve used man in the middle attack to flag your post after you’ve posted it, so it can get scanned by AI and moderators would decide on how many more times that has to occur.
It’s not something you can have an opinion on though, that’s the hilarious part. Hahaha. It either is or isn’t.
In your mind it is or isn’t. In my mind it’s possible to develop some way by those that have the ability to do it. 
Edit: Once upon a time we couldn’t send rockets to space. We do now!
Then you may want to consider talking to someone about that. Having feelings and opinions on something like that must be a scary thing to be dealing with. You may need some help with that.
I know we should all be just like you.
Pff, that’s nothing. In my mind it’s possible to find a prime number that’s a multiple of 4.
I’m sure someone will figure it out one day 
Let’s hope not exactly like me, I don’t want the price of tequila to go up.
It probably already has!
No, seriously, guys, I think the theory of composite prime numbers may be the key to Snoopable End-to-End Encryption.
That’s just out-of-the-box thinking. 
Well it can’t solve 
2 2 communication problem
