I personally like the Samsung T5 drives but that was quite a few years ago. Today I would go with the newer T7 drives.
[https://seekingtech.com/samsung-portable-ssd-t5-vs-samsung-portable-ssd-t7-touch/|Samsung Portable SSDs: T5 vs. T7 vs. T7 Touch]
The issue you face is the interfaces your system series offers. The Thunderbolt 2 ports offer up to 20 Gbps I/O each and the USB-A ports up to 5 Gbps I/O each. The newer Thunderbolt 3 ports in the 2016 models onward offer up to 40 Gbps via USB-C connections.
Even still having a fast interface on your system still is limited by the technology of the drive. A SATA based drive won’t be able to match the SSD’s speed, so I don’t think you’ll get the same performance.
If you need something faster then you need a RAID setup using your Thunderbolt 2 port, sadly, the direction for most of the RAID systems is embracing USB-C or enterprise based connections which are just not portable.