Custom joins (probably raw)

SELECT 
    a.code AS approval_code
  FROM schema1."Forms" a
  INNER JOIN schema1."FormTemplates" t
    ON a."FormTemplateCode" = t.code
  INNER JOIN LATERAL jsonb_each(a."additionalData") AS kv(key, value)
    ON TRUE
  INNER JOIN LATERAL jsonb_each(t."additionalDataFormats") AS tmpl(key, value)
    ON tmpl.key = kv.key

SELECT 
    a.code AS approval_code
  FROM schema1."Forms" a
  INNER JOIN schema1."FormTemplates" t
    ON a."FormTemplateCode" = t.code
  INNER JOIN LATERAL jsonb_each(a."additionalData") AS kv(key, value)
    ON TRUE
  INNER JOIN LATERAL jsonb_each(t."additionalDataFormats") AS tmpl(key, value)
    ON tmpl.key = kv.key