CPU vs GPU for mining.
Which would be better choice, a Ryzen 5/7 or rx 4xx/5xx, for cryptocurrency (Monero/Zcash/bitcoin...) mining?
Nvidia 1070 over both for monero i think
BAD advice. Nvidia cards do not excel in mining Monero as compared to AMD cards. Generally, AMD is for Monero/Cryptonight while Nvidia is for Zcash/Equihash. Any decent miner should know how much better AMD is for mining monero.
Anyway to answer OP's question, go for the GPU mining. Mining with your CPU is less profitable because of the lower hashrates, higher cost of hardware, and inefficient power consumption. GPUs on the other hand, have been constantly fine tuned for doing exactly what the CPU is not powerful or efficient enough to handle. GPU mining all the way.