Also don't forget that you can file a support case and ask for a custom field, in your case probably a node (community (global), category, board) level custom setting which will then be editable in Admin > System > Settings List Editor and can also be updated via API (still using v1 for that as support usually struggles to make them work in API v2).
As kkritika mentioned, there is (technically with custom settings as well, but less likely) a risk that someone accidentially overrides your custom content, something that may help to avoid that is using the title field of the custom content to clearly state that this should not be touched...
