Press F2 to enter BIOS setting.

Initial setting:
Security: Set Supervisor Password: [empty]
Boot: Boot Mode: [UEFI] <= leave as is.
Boot: Security Boot: [Enable]

Install Ubuntu (it worked with 18.04 and 20.04) from a USB drive.

1. Enter UEFI (BIOS) with F2 once Acer appears
2. Boot tab’s [Secure Boot] is enabled.
3. Security tab’s make sure a security management password is set [Set Supervisor Password]. This will enable the [Secure Boot Mode] functions.
4. In Security tab, execute "Restore Secure Boot to Factory Default", press F10 to save, then reboot once more into UEFI/BIOS with F2
5. Back to Security tab, enter [Select an UEFI as Trusted for Executing], HDD0 (or change if other drive), ../ Ubuntu / grub64x.efi, Yes. You may need to enter a name for it before click Yes to save it.
6. In Boot tab, disable Secure Boot
7. Move the [ubuntu boot] up to the first place.
8. F10 to save, exit and reboot.