Trying to install ina a partition instead of a full disk install, installer fails...

[T0mu]

... msg in logs lookspeculiar.
it seems it requires a lot of space..
Automatically determined minimal disk image size as 1.4T, current image size is 1.8T!

tik.log

[TobiPeterG]

Ah I've seen this before: systemd/systemd#38315

How is your disk layout? I'm pretty sure the 1.8T is the size of the disk overall and 1.5T are already used. The sized in the error message are wrongly calculated.
Did you delete existing EFI partitions?
I'm pretty sure systemd recognized one of your EFI partitions and can't resize it to the desired size. If this is the case, please try to delete the EFI partitions you currently have (and make sure everything on them is properly backed up) and retry the installation. Afterwards you can recreate the EFI partitions (though note that their UUID will change, so you will probably need to edit the /etc/fstab of any Linux trying to mount it) :)

Please paste the output of lsblk /dev/YOURDISK