you could use old reddit to easily delete/backup your data. just bookmark this and load it. reload if necessary. It will load oldreddit, then there will be options to backup your data

javascript: (function() { window.bookmarkver = '1.4'; var isReddit = document.location.hostname.split('.').slice(-2).join('.') === 'reddit.com'; var isOverview = !! document.location.href.match(/\/overview\b/i); if (isReddit && isOverview) { var cachBustUrl = 'https://raw.githubusercontent.com/j0be/PowerDeleteSuite/master/powerdeletesuite.js?' + (new Date().getDate()); fetch(cachBustUrl).then(function(response) { return response.text(); }).then(function(data) { var script = document.createElement('script'); script.id = 'pd-script'; script.innerHTML = data; document.getElementsByTagName('head')[0].appendChild(script); }).catch(function() { alert('Error retreiving PowerDeleteSuite from github'); }); } else if (confirm('This script can only be run from your own user profile on reddit. Would you like to go there now?')) { document.location = 'https://old.reddit.com/u/me/overview'; } else { alert('Please go to your reddit profile before running this script'); } })();

for more info go to this link PowerDeleteSuite