12V-2x6 Cable / Adapter for ATX 2.0 PSU

Apologies if this question has been asked multiple times before, but really is for peace of mind. Tldr;
- Bought a Seasonic Prime 850W 80 Plus Platinum in 2020,
- Currently upgrading system, including an ASUS Prime 5070ti OC 16GB,
- Wanting to use some of the older components (CPU cooler, PSU, SSDs, etc),
- PSU is the old 2.x standard, and not the newest ATX 3.1 standard, but noticed several companies selling cables / adapters; including CableMod.

The case is an ASUS AP201, so not too small like SFF, but not an ATX case either. I wondered what cables or adapters I actually need, so that I can safely install the GPU whilst reusing my old PSU.

Kind Regards