What's the best Flex ATX PSU?

I'm trying to figure out what the most energy efficient Flex ATX PSU is.

I have a PC right now with a Ryzen 9 3900XT and RTX 3080 but I find that I don't really play demanding games and I'd much rather sell my powerful components and buy second hand cheaper, less power hungry, more power efficient ones.

For now I'm thinking CPU: Ryzen 5 5600 GPU: not sure yet, maybe RTX 3060