Personally I always prefer the something else method. I would ensure Fast Boot and Secure Boot are disabled in the BIOS and perhaps forget about UEFI altogether.
Starting with the downloaded .iso, double-check the SHA256sum against the one Zorin provides to ensure it is not corrupted.
Then I recommend you create a Ventoy thumb drive with Ventoy2disk and go with mbr. Then just drag the .iso to the Ventoy thumb drive.
So forgetting about UEFI for the moment. GNU/Linux uses MiB (MebiBytes), not Mb (Megabytes), so I would use just two partitions using the 'something else' method.
So for the 'root' partition (labelled '/' without the single quote marks) I normally create one equivalent to 80 Gb, in MiB this is 76293 MiB (GB to MiB Conversion Gigabyte to Mebibyte Calculator).
Then the rest of your drive create a /home partition.
Ensure both partitions are formatted to Ext4. You do not need a 'swap area/linux swap' partition as you have plenty of RAM and you are using SSD's.