This is solved. Putting two potential fixes below for anyone who might be encountering this issue. Documentation on this error is super sparse, and I gathered bits and pieces from multiple posts.
Fix 1:
Upgrading from 8.2.x to anything higher than 9.0.8 will result in this error. Start your migration from 8.2.3 to 9.0.8 then upgrade to latest version from there.
Found this fix on a forum where the user had put in a ticket with Microsoft, and Microsoft came back and said the upgrade from 8.2.3 to anything higher than 9.0.8 is unsupported. Don't know why the latest update wouldn't include fixes for this upgrade limitation, but, hey, that's Microsoft.
Fix 2:
Comment out the below pieces of code in the ServerRelease.xml (path: \Program Files\Dynamics 365\LangPacks(LanguagepackID)\Xrm\sql\9\ServerRelease.xml). This is not recommended, but was an alternative solution offered by Microsoft.
This was successful when importing an organization in our dev environment.
Hope this helps to anyone in the same boat!