I've gotten an abandoned Samsung Galaxy Note SM-P900 tablet, which is supposed to go to charity. Unfortunately, it sports an Android 5.0.1, a lot of APKs don't install, and many websites can't be accessed by Samsung's bundled browser due to not having a valid security certificate.
Can I upgrade the Android version and otherwise make the life of this device's user less miserable?
I understand there are no relevant official updates, as explained here:
How to upgrade my Android device to latest Android version
But I don't mind flashing this device, and obviously don't mind losing anything stored on it (I've already reset to factory settings anyway). I have a PC running Linux with adb installed, I have some USB cables, and I have a bit of time to spare.
Oh, I should mention a constraint: No use of any Google or Samsung account during this process.