Do you see the Apple Account user's name when you attempt to update these apps? Do you recognize that person?
Could a friend or relative have used your Mac to download these apps?
No one here can say if the Mac was owned by someone else. Only Apple might be able to confirm that. Where did you you buy the Mac? Can you check with the seller?
Bottom line on the apps, only the account that installed them can update them. If you want the apps and wish the updated versions, you will need to delete them and redownload them with your Apple Account. If they are paid apps, you will need to buy them.
If you want to know what Apple can tell you about the Mac, speak to Apple Support.
World-wide Apple Support -
Contact Apple Support - Apple Support
Support by phone, email or chat -
https://getsupport.apple.com/
Apple Support by Twitter -
https://twitter.com/AppleSupport
M1 Mac mini, macOS 26.2; Watch, Series 10 GPS-only, watchOS 26.2; iPhone 16, iOS 26.2.1; TV 4th Gen, tvOS 26.2 HomePods, audioOS 26.2