Thanks for reply!
I don´t think to use that external drive for Windows, on that laptop I just installed different libraries on the second internal drive with NTFS file system.
So the external drive will be used by MacBook Pro, with the old one firstly (2015) and then with the new one (I hope in 2-3 months) - installing software and just having all libraries installed on the drive. I don´t know if the APFS will be well written and well read by the old MacBook Pro or I´d better use Mac OS Extended (Journaled), or is it the same in modern times?
If I use NTFS - I understand that it´ll be necessary to install everything from Windows, but for using with MacBook Pro - will it be necessary to use Paragon or some other app to manage this external disc? Or Paragon will drop the velocity of the drive? SSD is WD 4TB and I´ll use it with Thunderbolt 2 adapter for better performance (it´s working really fast), want to fill it with different libraries I have (2 or 3 TB, among them VSL, EWQL, BBCSO, Cinesamples, NI etc) - very laborious task - so don´t want to make a mistake on file system and then repeat installing everything.
So need your advice for my particular case - you know everything in this camp!