alternatives to amazon fire for reading library ebooks?

We don't buy from Amazon for 'cider press' reasons that I don't want to discuss here.

I download ebooks from Arkansas Digital Library Consortium and to do so I have to go through Amazon because they are the boss of me since it's their kindle.
I use wifi at the library to load the books onto the kindle and once they are downloaded I can read at home off line.

Does anyone else download library books on a tablet other than this one?

I don't want them on my phone but might try to get another tablet if it would work.

My eyesight is such that the larger type face that I can use on the tablet is very helpful and the online resource has more books available than our local library.

thanks for any advice!

Why not use a Android tablet and the Hoopla app.
I've been using this for awhile to get books music and movies from the library. 7 titles per month.
I've also got the Libby and Kindle apps.
Thrift stores are a good place to find used tablets if you can't afford a new one from somewhere like Temu they have tablets for about $30.  

My library lets me use the Libby app, and download them to a  Kobo reader.

I can also buy or download free ebooks and put them on my Kobo (just not from Amazon, which I also did not want to be tied to).

Kobos are often available used near me.

In what form or format are the ebooks available, and where are you allowed to download them from? There are lots of free ebook reading options available for windows, android and linux. (Mac too, I'd bet, but I haven't looked into it.) There is at least one free converter for windows and linux to convert ebooks from one format to another, though it may be difficult or impossible to use on proprietary ebooks like those controlled by kindle.

We might be able to help you find more resources if we knew a bit more about your situation and needs.

My library uses the Libby App too. This has enlargement features for the text and the background can be altered - I use the sepia setting. Only snag is it releases a section of pages at a time and can't be used offline. Downloads go to a smallish Hp laptop.  This is slightly problematic as when there is no internet/power only the already downloaded pages are available. Power outage yesterday and my husband set up the mobile phone as a 'hot spot' and there was internet available and the computer worked on its battery. Lucky me!

I just thought of something that may help. If you'd like to use your kindle, but download the ebooks elsewhere, your kindle (or kindle app, on another device) has a unique email address. You can email ebooks of many formats to it. After a little processing time, it will show up in your kindle library. I used to do this a lot with books from project gutenberg. I found that I was happiest with the results if the ebook I was sending was in epub format.
If this sounds like something that might help, here's a link to instructions. If it's a little intimidating, let us know where you're hitting a snag and maybe we can walk you through it.

thanks everyone!

to answer t. melville...
what I do now is go to the arkansas digital library consortium site using the library's wifi on my amazon fire tablet.  I check out ebooks for two weeks at a time.  To use the kindle app on the tablet I have to be signed in to amazon.  Once the books are in my 'library' I can download them all while still on wifi and then read them off line.

Some of the nooks are available as epub and something else I don't remember.  I tried epub once but was unable to read off line...maybe I didn't set it up correctly?

I am able to change the font size off line and use the blue light filter.
I like it all except having to go through amazon.

I don't buy books although I have a few that I own on kindle also that I suppose I would lose if I switched to a different format.

I am not online at home except using limited data on this phone.

to be clear...the county library is not essential to checking out ebooks from the digital library...I could do it from home if we were online here.

now I'm reading about the kobo ereader.
https://en.wikipedia.org/wiki/Kobo_eReader

One of those sound like what I might want...

I'll look tomorrow at the library to see what other ways the ebooks are offered.