The latest handset to go through the teardown procedures performed by the folks at iFixit is Samsung's new flagship, the Galaxy Note8. It's managed to fare much better in the repairability department than the recently torn down Essential Phone, but that doesn't mean the Note8 is easy to get into - at all, unfortunately.
Any repair you may want to make requires you to remove the glass rear panel, which is a challenging task to accomplish because of how much adhesive is holding it in place. If you want to replace the screen, you'll need to remove both the display assembly and the rear panel - both fragile, both secured with very strong adhesive.
On the other hand, the Note8 has many modular components inside, including everything that normally experiences wear. This means you can replace bits and pieces independently - if you manage not to break the glass while getting in. Another plus for the new Note is that all screws are standard ones.
The battery can be replaced, but this is made "unnecessarily difficult" by the tough adhesive used and the aforementioned glued-in rear panel. In the end, the Galaxy Note8 received a 4 out of 10 repairability score (10 being easiest to repair). That's a far cry from the Essential Phone's 1 out of 10, but even so it means you're better off not attempting any repairs on a Note8 on your own.
Well, this one is gonna get junked by modern day hipsters in less than two years to get the newest shiny junk-again-in-two-years-or-less hipster device.
Note 8 uses Murata batteries, Japanese batteries that are best in the world!
Then don't buy a flagship phone from one of the top brands. There is plenty of choice what fit your checklist other than flagship phones.