You can now add Bluesky and Mastodon your organisation’s social media accounts in organisation settings → organisation details. This adds corresponding buttons to News Builder footers and lets you insert the new social media links into templates with {insert: social media ...} substitutions.
Also, these two services are included in the list available to add to member individual’s additional handles (using @+ after an individual’s email address; you can add additional services anyway, so this just saves that step).