Broken upgrade path 7.7.8

We are on 7.7.8 and the upgrade option doesn’t work, freezes at step 2. Can’t run the Quick repair because the repair will break Suitecrm hard by changing permissions on the module en_lang files to immutable, unable to delete and completely disables the CRM.
Because our site was hacked a few weeks ago, I thought the best path forward was a clean install of 7.7.8. Copy over the /custom and /cache files along with .config and config-override.php files. Before anyones says it, yes, we were very careful on resetting permissions. This CRM is so brittle, permissions are key to keeping it somewhat running.

At this point, after 30 man hours, we have SuiteCRM running on a SiteGround host, with no errors showing in suitecrm.log. However, the upgrade path is broken. Does anyone have any ideas to get us upgraded?

i think siteground or similar servers are very sensitive to permissions and you might spend more time fighting the server rather than doing actual job, so best thing can be you setup a local host (i.e via XAMPP or similar) and deploy your instance on it and get your upgrade running. Since this would be your own PC, you can set any permissions and open any paths that would get the upgrade wizard running. Plus you can view apache/php errors log easily.

PS: you can check for Logs on siteground if that can give you some details.