The MacBook has USB-C ports that only support USB, DisplayPort 1.2, and HDMI 1.4 (using passive adapters). Active adapters can convert DisplayPort to VGA, Dual Link DVI, and HDMI 2.0.
USB-C/Thunderbolt 3 devices may include a billboard USB device or USB Power Delivery (PD) information that can tell the computer what kind of device it is. This way, your MacBook can tell that the device is Thunderbolt 2 and give you that information that it won't work.
The Apple Thunderbolt 3 to Thunderbolt 2 adapter will work to connect Thunderbolt 2 devices/computers to Thunderbolt 3 devices/computers which includes the MacBook Pro, iMac, and your TB2 disks.
There is no way to connect a Thunderbolt device to a computer that doesn't have Thunderbolt.
There is no way to add Thunderbolt to a computer (unless it's a PC with Thunderbolt add-in card support).
What you can do is transfer the hard disk inside the TB2 disk to an enclosure that uses USB.
Or you can connect the TB2 disk to a computer with Thunderbolt, enable file sharing on that computer, and connect to that computer from your MacBook.