Discross is an option, for Discord: https://browsedns.net/topic/6438/discross-discord-on-switch-kinda
This is not usable on Switch, but Beeper allows you to link multiple accounts (eg. Facebook, Instagram, Google, Whatsapp, etc) to a single Matrix account: https://www.beeper.com
If there's enough interest I could look at getting a Matrix client that works well in the switch browser, but it'd be for messaging only.