Chosen Solution

So the hdd inside my mac is dying, everyday there are more bad sectors and right now i cant afford to change the internal ssd, so i need a temporal solution until i change the thermal paste for liquid metal/ram to max support ( i will try 32gb). So i need the cheapest and fastest/or at least trouble-free solution, i am thinking on a thunderbolt 2 to usb 3.1 adapter but i cant really find one, i already have an usb 3.1 ssd. -I already have a bootcamp instance on my system. It is possible to avoid all the bootcamp thing and just install windows directly on it? (keeping the drivers )

There is no Thunderbolt2 to USB adapter, there is a Thunderbolt3 (USB-C to USB) adapter, but that won’t help you here. The best you can do is use the USB ports directly on your system which is what I would do. Or get a Thunderbolt2 drive which are getting hard to find if you want better performance. For now just stick with macOS until you get your system repaired.