GBAtemp.net - The Independent Video Game Community

Official Discord client: with a lot of compromises and rewriting, unlikely (browser engine is very outdated), and WebRTC for voice chat would probably be out of reach

Unofficial Discord client: has been done many times on 3DS and maybe Vita, but they always get abandoned and never work again, and there is a risk of account bans because third-party clients are disallowed

2010s portables don't exactly have many chat options out of the box (3DS used to have SwapNote/SwapDoodle, Vita used to have working text chat) or in regards to homebrew, but if you're eager to use them for chats anyway, platforms like IRC and potentially XMPP are your best bet

Never tried it, but here's a Vita client: https://github.com/devingDev/VitaCord . They dislike 3rd party stuff? Wonder if BetterDiscord is keeping up the good fight. I had an AIM client on the old DS once too.