From what I remember, sorry a bit of faded memories, the first important metric for Satoshi was the block time target of 10min. It was likely a compromise but mainly focussed on security. To my knowledge a smaller block time, particularly in the beginning of the Bitcoin blockchain, would've had less security and stability (don't press me on that, though). The likelyhood of certain attacks rises with significantly shorter block time. Much larger than 10min isn't nice either, not in terms of security but user experience.

Initial block reward of 50BTC seemed like a sweet spot for Satoshi, large enough to trigger interest (and maybe some greed ) and attract more distinct miners to increase decentralization and security by more proof of work of more individual miners.

And then chosing a halving period in the time frame of about 4 years resulted in the metric of 210,000 blocks. It could've been that value of initial block reward and halving intervall are intertwined. But, frankly, I don't know or remember past discussions about that and I'm only mildly interested in those.

In my perception the most important metrics for Satoshi were stability and security of the blockchain, a reasonable length of the halving period and not reaching max cap too fast or too far in the future.