I have just changed an older tablet from Windows 10 to Zorin OS ( based on Ubuntu and Linux is new to me ) and in the Software center Gramps is listed twice! Once under ‘Zorin OS’ as an apt package and once under ‘Flathub’.
The Flatpak is recommended. You will get the latest release, whereas the apt package is likely to be old. Zorin OS 17 is based on Ubuntu 22.04 which has Gramps v5.1.5 in its repository.