APFS + EXFAT + MacOSE on 4TB ext HDD BAD idea

I upgrade my MacBook pro to 10.13 (17A405) and have formatted and partitioned my newly bought 4TB external Seagate Backup Plus with GUID Partition Map as follows:

1. 2TB APFS for Lightroom and Photos libraries

2. 1TB Mac OS Extended for Time machine

3. 1TB ExFat for files and transfer

Now I am

1. Dealing with a crazy slow APFS partition and while I am writing this message I have to wait another 21 hours to simply copy a 200 GB photos library from the APFS drive to ExFat...

2. If I want to disconnect this drive I need to turn off my Mac or it won't eject / unmount.

3. I don't know why it is so super slow, it takes between 5 to 20 minutes after connecting this drive to my laptop for the system to recognize and mount the APFS drive.

I don't know what I can do to improve it, so any advice is welcome.

I will consider a reformat of the drive after I have managed to copy the photos library to another drive, however now 21 hours just became 22 hours......