@SahilSakolkar apologies but I’m slightly confused on the order of events here. If I understand correctly, you’re saying that you installed Brave some time ago and then at some point, downloaded the Brave Group Policy templates onto your machine and modified them and the browser continued working without issue up until the most recent update?
If that is the case and you’re okay with starting fresh (which I assume you are given that you already tried uninstalling), I would recommend the nuclear option here. That is, uninstall Brave via Windows Add/remove programs and make sure you elect to delete the associated browsing data as well when prompted by checking the box during the uninstall process, shown in the image below:
Then, go ahead and delete any Brave related Group policy templates/rules.
Once everything is deleted, download and reinstall the browser fresh and let me know if it launches normally.