If you are skipping to sda5, then you must have MBR.
Windows only boots in BIOS mode from MBR and only in UEFI from gpt partitioned drives.
UEFI strongly suggests gpt, but Ubuntu will let you install in UEFI mode to a MBR partitioned drive (probably should not).
But you cannot dual boot from same drive if Windows is BIOS and UBuntu is UEFI.
Both Windows & Ubuntu install in the Boot mode you select to boot install media. And both systems then need to be in same boot mode.
Microsoft has required vendors to use UEFI/gpt since Windows released in 2012, so new hardware is all UEFI. UEFI has BIOS mode only for backwards compatibility as some large companies may want to keep all systems in same mode until they upgrade everything.
If you just installed Windows, I might suggest reinstalling it. But installing Windows is a hassle compared to Ubuntu. I now can install Ubuntu in UEFI mode to a partition already created in less than 10 minutes. My one Windows system took most of the afternoon to do the upgrade from older version.
But very new hardware will be supported better by Windows as that is the major market. It can take a while for the Linux folks to update kernel & drivers for new hardware & then get it including in a distribution.
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