Pixels are the best phones to change ROMs (it's peculiar but it's true). Take a look at GrapheneOS. I'm running it on a Pixel 7 Pro and all my apps work.
I agree it's full of stereotypes and bad jokes, but it's a show that's easy to watch and that doesn't require concentration. I am a Physicist and an Engineer myself, very much a geek and generally considered to have a very twisted sense of humor, but I still enjoy watching this show, generally while doing other things on the side.
I don't know, I have been using them for more than a year and am SUPER happy. I use their mail, their kDrive sync and calendar/tasks and have had nearly no problems. And when I have had a problem, I have gotten very fast email support, and they even pushed an update when I let them know there was a problem with the keychain acquisition on KDE. Honestly, it's the best experience I have had ever with any cloud provider. I even have WebDAV support!
Not really! You can find the source code for almost everything in their github (I say almost because I haven't checked if everything is in there, but I know the clients are because I've looked them up). Besides, aside from offering extremely competitive prices, they are privacy friendly (don't offer end-to-end, but you can read their privacy policy) and use a very ethical infraestructure. I seriously recommend you check infomaniak up; I have been using them for 2 years and couldn't be happier.
It is already open-source. All of the source code is on their github and, for docs, they use an implementation of onlyoffice very similar to the one in Nextcloud
But the post says before the integral, so I understand what they did would be $dx \int f(x)$, which is disgusting