Tablets are still a thing? Large phones and Laptops is what my bubble uses.
I'm typing this on a Samsung Tab A with a bluetooth keyboard. It's actually a pretty slick form-factor -- 9.7" screen, 1024 x 768 dispaly, 128 GB additional storage, and converts from a deskable or lappable landscape to portrait in under a second. Charge lasts all day.
The basic concept of a mobile device whose display is separable from its keyboard is _wonderful_. Laptop hinges suck.
That's the hardware -- and you can do better on several counts (memory, ROM, MicroSD, display) now.
But for two major limitations:
1. NOBODY has a decent keyboad, and there is NO standardisation for cases, outside a minsuscule handful of products. Samsung's Tab 3S has a keyboard ... five rows -- no function keys. Which kills off a whole set of applications right there. The keyboard I've got (Logitech Type S) was broken from the start, and Logitech have abysmal warranty support. The keyboard is no longer made (they claim), and loses keys and other function over time.
2. The OS and applications space is abysmal. Here I'm including iOS and Android. Neither Google nor Samsung support updates to my device (it was apparently EOL as I was buying it). It's also not supported by CyanogenMod / LineageOS. The best thing I've found since getting this has been Termux, a Linux console environment, which offers a small but very, very, very useful set of utilities. Even that is crippled by what appears to be a bad terminal emulation (exceptionally slow on any scrollback), background-process termination (I'm never sure I'll find my sessions when I return to them), and something insanely buggy with SSH emulation.
iOS of course doesn't even have a userland / console space.
I'm looking at the Samsung Tab Pro line. It's expensive -- more than twice the price of an Asus Chromebook, say, but has the benefits of a folio-case and seperable keyboard form-factor. It seems to come with Windows 10 rather than Android, and I'm trying to sort out if that can be converted to either LineageOS or Linux.
The surveillance-capitalism market of Android / Google is no longer tenable. The App ecosystem is fatally broken. Google's own apps (notably Chrome) are beyond frustrating. So really, the faults are all on the OS/applications side.
I've some fairly strong reservations about installing Linux on a tablet as I doubt that Linux tools will play well with a touch-based surface (and touch itself ... has massive problems). In particular, the inability to distinguish a touch vs. click/drag action, the inability to navigate with the pixel-perfection of a desktop/mouse (though with high-def displays even that is pretty dicey these days), and the lack of multi-button mouse equivalents. I find all quite annoying.
But for straight console-mode operation within Termux, the tablet's actually reasonably useful.
What would help here?
1. Size standards on devices, including port and switch locations, such that cases could be designed for them across vendors. There are cases which work for only specific variants of Samsung model lines.
2. Keyboard standards, including interactions with keyboards, "special" key placement, and standardisation on a six-row, ~78 key standard. Samsung's 64-key error on the Tab 3S is absolutely inexcusable.
3. An alternative to straight-touch interfaces.
4. Bootloader unlocking and a sane standard for non-cloud device backup.
5. Mandated, effective, and usable privacy controls.
Personally, I've given up on using Linux from Android. I'd love to, but it's next to impossible, you'll run into other issues you haven't even seen yet; for example, my phone doesn't even have ext support for the sdcard; I'm stuck using fat32 for a 32gb partition. You also can't mount a network drive with fuse and expect to access it from another app.
If you want a software keyboard, use hacker's keyboard--it does a full keyboard layout with alt/Ctrl/other keyboard keys. If you want a physical keyboard, you shouldn't use a keyboard case anyways, a full size keyboard is far easier to use. You can get a microusb numpad-less keyboard for around $10-15 online. Alternatively, just get a full 100+-key Bluetooth keyboard
If you want updates, buy Google and/or deal with unofficial community updates if you can get them, because only Google updates their devices. I'm stuck on lollipop because Verizon has decided not to release Marshmallow in the US (VZW Moto E2 has MM in EU only)
The adb backup/restore commands may also be of some limited help to you. (They use archives that aren't openable, but they do work)
Google/Nexus devices have no damned onboard storage. That's a fail. I don't do cloud.
The lack of usable / findable docs on this stuff is another PITA.