Mightytext does some of this for Android phones: It lets you read and send SMS on your phone from your computer. It also shows notifications from your phone when they happen. It's an app on your phone and a website on your computer.

No affiliation; just a satisfied user.

I don't use Mightytext a lot any more except for 2FA since I mostly use Signal for messaging. And of course Signal has an Electron app for desktop that works for both text and voice.

For file and photo sharing I just use Dropbox. I have Dropbox on my phone set to upload photos as soon as I take them, which means they also show up immediately in a folder on my desktop (on MacOS. I assume this works in Dropbox for Linux but haven't tested it.) Caveat: Dropbox still doesn't support ARM Linux. It's Intel only. WTF Dropbox??

Also curious. I keep messages.google.com in a pinned tab but the number of times I have to go find my phone and re-authenticate is too damned high.

I don't know the specific ones, but there are android apps that replace Google Messages (dark pattern warning: enabling this makes your previous messages inaccessible as Google Messages won't let you read them unless it's your default SMS app) as well as apps that can send and receive in parallel to Google Messages. I'm not sure if there are also apps that can read your message history out of Google Messages.