You can't access the normal Reddit site behind a VPN either. The only solution is to use a private frontend like Redlib with LibRedirect, to automatically redirect all Reddit links to Redlib.
Andromxda
An old Android phone with postmarketOS (basically Alpine Linux) is a pretty good Raspberry Pi alternative
I understand why, but dumbphones aren't good solutions for most people's problems. They have many disadvantages, for example they don't offer secure (encrypted) communications (except for the Punkt MP02 which has Signal support, but it also has other issues), you don't get a proper keyboard, no touchscreen, and you often can't even look something up on Wikipedia. You can't listen to music/podcasts, use the phone for navigation or take notes. Most people just end up getting frustrated by a dumb phone, and switch back to a smartphone and continue wasting their time on social media. A decluttered smart phone with restrictions for social media usage is much more effective. The videos I linked in my original comment explain this pretty well.
Right, that makes sense
You. don't. need. a. dumb. phone. to fix your social media addiction
Basically every modern smartphone has features that allow you to restrict your usage of distracting apps/websites. You can recreate a minimalistic dumb phone on your smartphone using free & open source software or your operating system's built-in tools/features. There are a few good videos about this:
The one thing that impresses me about consoles though: How tf do they manage to run even graphics-intensive games on such low-end hardware? I mean sure, frame rates aren't great, but the fact that these games still run and are somehow playable amazes me.
Or use LibRedirect to do it automatically