Your not wrong, but you seem to be missing one significant detail: we have altered the biosphere even more by not engaging in nuclear activity, instead opting for less-scary-but-worse alternatives like coal, oil and gas.
This could be a convincing argument 70 years ago but we have other options now - mostly batteries and renewables.
"But what about the cobalt mines?" - that damage is limited in both space and time
You're not wrong, but you seem to be missing one significant detail: if we had invested in renewable energy resources like solar and wind to begin with, we wouldn't have needed (as much) assistance from nuclear, coal, oil, and gas.
>we have altered the biosphere even more by not engaging in nuclear activity
You imply that we could have made enough nuclear plants to replace coal, oil and gas and that would have prevented the effects of fossil fuel consumption.
That's not the case. It would have been entirely impossible to make enough plants to even replace coal and oil fast enough, and even if we did, electricity is only 25% of emissions.
Historically, yes. We have good alternatives now, though. What’s stopping us moving off carbon fuel is not the viability of alternatives.