Don't buy cheap tablets, they're never worth your time. Shop fleaBay for a Samsung Tab S6, S7 or S8 depending on your budget instead - you'll be much happier with the outcome.
I'm still using my 2019 Tab S6 for Netflix, Reddit, PDF reading and annotation, comics and occasionally ebooks via KOReader. Great device, absolutely worth the ~$400 I spent on it on fleaBay ~3-4y ago.
If AMOLED is a must for you the Tab S6, Tab S7 Plus, Tab S8 Plus or Ultra and any Tab S9 model are where you want to start. I'll replace my Tab S6 when the 11in Tab S9 drops below ~$400 secondhand.
In 2017 I got myself a lenovo tab 8", Android 6, 3GB of RAM for less than 120€. Thanks to AOSP, I got it on Android 10, and it's still kicking 6 years later. Get tablets that you can own! (ie Unlock bootloader).
I wish LineageOS would support more tablets. I've got it running on an old OnePlus 6 I use as a Plex client and not much more and it just works, and I get all of the latest security updates etc. I know there are other ROMs out there, but none of the big ones support semi-modern tablets.
I needed a "tv" for my camper van. Cheap Lenovo M10 works fine in that role, mostly as a Plex client. The big complaint is I can't get rid of their stupid app bar and can't find a custom ROM. But for what it does and what I paid, it's fine.