https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=nextcloud
A common misconception IMO is that running and owning your own infrastructure is somehow more secure. To that I lol, and I’m confident that the thousands of AWS/GCP/Azure/iCloud security engineers are all doing a more thorough job than you can. At the very very least they receive embargoed bugs which they often mitigate before the general public.