EDIT
Warning about Wikipedia in pocket: Page-Internal links will mostly not work inside the pocket-app. Even if you try to "sync to pocket", they do not work correctly. So, the whole page-internal menu structure of a Wikipedia article simply will not work ! Also, pocket will completely edit out any table lines. And large tables cannot be scrolled horizontally, so they just are mainly outside of the visible page (this can be tested on any smartphone) Also, all sections of the page will be opened up, and you can't close them to quickly skip to the next section.
Reading Wikipedia from within pocket is a terrible user experience ! Test it out on a smartphone or tablet before buying any device specifically for this !
Test on a Kobo ereader.
I have successfully tested this on a Kobo 'Aura H20 Edition 2' ereader, and can confirm that in principle and within the limits explained above, it works as expected:
- the Pocket App will navigate between pages which were previously saved on your account. If you press a link to a non-saved page, the app will ask you whether to open it in a browser or to sync it to pocket. The good thing is that navigation works the same way as in books, in a paged experience (no scrolling). However, I experienced some issues syncing freshly saved contents to the ereader, but this could be due to the pocket-account present on the ereader, which I was not allowed to change.
- The browser can be found under beta-features, and it works just as a normal bare-bone browser without any whistles or bells. There's a dedicated 'save to pocket' button next to the address bar, which can be handy. Browsing webpages is not a pleasant experience as the scrolling causes horrible ghosting, and therefore needs a lot of patience. Also, due to the B/W screen, some contents can be hard to read as they may lack contrast.
Old Answer
This video from 6 years ago shows that browsing works as expected on a Kobo, so this should partially answer your question: you'll be able to read wikipedia in the kobo browser. Though note that the kobo browser, after 6 years, officially is still in beta.
Although I have not tested this (yet) on a Kobo, I can confirm that you can read the whole Wikipedia from within pocket. Long-click on any link and choose 'save in pocket'. The linked article will immediately sync to your pocket library, and from then on the app will automatically open the pocket-version of that page. Since Pocket is available since many years on Kobo, I would suppose this will work also on a Kobo device, as long as you're connected to the Internet.
(I can't test this right now on a Kobo device, but I might have a chance to do it in the next 10 days, and would then update this answer. )
Furthermore, I'd recommend you to read through this thread, where the OP has a very similar question to yours. Just to cite one answer from there (which reflects my experience):
If Wikipedia is really the thing you wanna do on the device, I'd recommend getting an e-ink device that is powered by Android on the backend and can load apps from the Play Store (or at least sideload them somehow). My personal feeling is that the Android app for Wikipedia is the best way to read Wikipedia articles, and I already use a normal android tablet with it quite frequently.
(I myself have a Boox device and would not change it, simply for the fact to be able to freely run android apps).
