FAIL : first and fresh install of CiviCRM 5.36.1 on BACKDROP 1.83
The URL looks off to me. The link to the dashboard should be /civicrm?reset=1 and to the status page /civicrm/a/#/status. /civicrm/a/ is not a page and I also get &quot;Unknown path&quot; when navigating there in a Backdrop install. Perhaps check to see if your URLs are being rewritten in apache?