All HD are the same, actually, except in quality, there are only 4 HD mfg. on earth (conventional HD).
Your Segate WILL let you "just drag and drop" files, you dont have to use it as a time machine.
Go to FINDER> preferences > general > check boxes hard disks, and external disks
your seagate will show up on desktop, open it, drag and drap whatever you want.
Any NEW out of box HD that has any software bundled on the drive to "improve.....help", .....ignore it, its all trashware , useless and sometimes worse.
All new in box HD should be formatted, and made to be a "blank brick" to do with as you want.
Segate external HD is fine, ...stay away from WD drives and youll be fine 😊
Your seagate backup plus......the "backup plus" part means this...... NOTHING
There are several HD that are labeled "backup plus", or "portable" , or "data plus"....etc etc.
all these catch words on USB 2.5" HD mean 100% absolutely nothing whatsoever. 😉
A hard drive is a hard drive is a hard drive. All USB 2.5" HD contents contain 4 things,..... a conventional HD,.. a sata card,.. the plastic/metal box, ...and the USB cable.