On the checkout page the address format is not assumed. Customer address format defined in the backend is ignored.
This is the format defined in backend
{{depend prefix}}{{var prefix}} {{/depend}}{{var firstname}} {{depend middlename}}{{var middlename}} {{/depend}}{{var lastname}}{{depend suffix}} {{var suffix}}{{/depend}}{{depend firstname}}
{{/depend}} {{depend company}}{{var company}}
{{/depend}} {{if street1}}{{var street1}}
{{/if}}{{depend street2}}{{var street2}}
{{/depend}} {{depend street3}}{{var street3}}
{{/depend}} {{depend street4}}{{var street4}}
{{/depend}} {{if postcode}}{{var postcode}}{{/if}} {{if city}}{{var city}}, {{/if}}{{if region}}{{var region}}{{/if}}
{{var country}}
{{depend vat_id}}
UID-Nummer: {{var vat_id}}{{/depend}}
Magento2 V 2.2.3 - default checkout page