The Pixel Tablet with GrapheneOS is the gold standard, but there's even more than just the tablets with LineageOS support if you are adventurous.

I was gifted a Samsung Tab A7 Lite, which is without LineageOS support. However, I've been able to flash TrebleDroid Generic System Images (GSI), which are vanilla AOSP images modified to support as many devices as possible. They come with no Google apps or services.

Nearly everything works as expected, performance is much better, and battery life is unchanged. I can even run Android 15 smoothly when Samsung will end support for my tablet with Android 14. If anyone wants a writeup to the best of my memory, feel free to reply.

keep your data turned off. you load the tablet with books or whatevers, you don't need no comms, hence nothing can leak.

second, you should get the device based on LineageOS support, so check their devices page first. there's but a handful of those, I was lucky to find a Tab S6 Lite for cheap and it's hella supported. if you have money to burn then look into Pixel tablets and such.

finally, when you eventually flash them, the battery life isn't great. even just having them lying around not doing anything in standby requires you to connect it to power every other day or so. had an iPad like 10 years prior, that thing could be left for weeks and still be available when you need it. sadly, no such thing exists here.

p.s.: not what you asked for, but take a look at old 2-in-1 tablets in the vein of Dell Latitude 5285/5290/7290 etc. those are fully featured i5/i7 machines, tons of RAM, expandable storage, you can install Linux on them with all the benefits and drawbacks that brings; battery longevity also ain't a thing here, but at least you can tweak everything (limit frequencies, hibernate, etc.)

The Google Pixel Tab with GrapheneOS. I got the most recently produced tablet that supports Lineage and it's very slow.

AFAIK, GrapheneOS supports the Pixel Tablet, which is probably the only truly secure android tablet on the market.

If you're willing to sacrifice some UX, there are some Linux tablets. A cheaper option could be a 2-in-1 chromebook that allows installing Linux.

Otherwise, you could try to degoogle your Samsung tablet by installing LineageOS on it, if it's supported.

What are you using to read comics, and is it available for Linux?

Being that you already have an 8 foot tablet, I assume you're looking for an OS to run on that. The only suggestions I have is possibly LineageOS, if it's compatible. Otherwise you're looking at replacing the hardware.

Is LineageOS available for it? I have a Samsung tablet I reflashed and I've been quite happy with it. Battery life isn't great, but it mostly lives in my bedroom, so not much of a problem.