how to install ubuntu and triple boot with high sierra and legacy booting win10 with dual disk drive?

I have a mac mini (5,1) with two disk drives, right now one is installed with macOS High Sierra, one is installed with Windows 10 as shown below:

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *500.1 GB   disk0
   1:               Windows_NTFS System                  104.9 MB   disk0s1
   2:               Windows_NTFS Windows                 499.4 GB   disk0s2
   3:                       0x27                         602.9 MB   disk0s3

/dev/disk1 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *128.0 GB   disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:                 Apple_APFS Container disk2         127.8 GB   disk1s2

/dev/disk2 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +127.8 GB   disk2
                                 Physical Store disk1s2
   1:                APFS Volume macOS                   32.7 GB    disk2s1
   2:                APFS Volume Preboot                 21.8 MB    disk2s2
   3:                APFS Volume Recovery                512.1 MB   disk2s3
   4:                APFS Volume VM                      20.5 KB    disk2s4

I want to partition some space(40G) on the disk which macOS is installed(disk1) to install ubuntu 20.04 server, and triple boot all three OS without install third party boot manager, what should be the right steps to do this properly, or is it possible?